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vector-toc-level-2"> <a class="vector-toc-link" href="#Optical_fiber"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Optical fiber</span> </div> </a> <ul id="toc-Optical_fiber-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Photophone" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Photophone"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Photophone</span> </div> </a> <ul id="toc-Photophone-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Free-space_optical_communication" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Free-space_optical_communication"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Free-space optical communication</span> </div> </a> <ul id="toc-Free-space_optical_communication-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>References</span> </div> </a> <button aria-controls="toc-References-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle References subsection</span> </button> <ul id="toc-References-sublist" class="vector-toc-list"> <li id="toc-Citations" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Citations"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Citations</span> </div> </a> <ul id="toc-Citations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bibliography" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Bibliography"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Bibliography</span> </div> </a> <ul id="toc-Bibliography-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" 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class="firstHeading mw-first-heading"><span class="mw-page-title-main">Optical communication</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 23 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-23" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">23 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A7%D8%AA%D8%B5%D8%A7%D9%84_%D8%B6%D9%88%D8%A6%D9%8A" title="اتصال ضوئي – Arabic" lang="ar" hreflang="ar" data-title="اتصال ضوئي" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Comunicaci%C3%B3_%C3%B2ptica" title="Comunicació òptica – Catalan" lang="ca" hreflang="ca" data-title="Comunicació òptica" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Optische_Kommunikation" title="Optische Kommunikation – German" lang="de" hreflang="de" data-title="Optische Kommunikation" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Optiline_side" title="Optiline side – Estonian" lang="et" hreflang="et" data-title="Optiline side" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Comunicaci%C3%B3n_%C3%B3ptica" title="Comunicación óptica – Spanish" lang="es" hreflang="es" data-title="Comunicación óptica" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%D8%AE%D8%A7%D8%A8%D8%B1%D8%A7%D8%AA_%D9%86%D9%88%D8%B1%DB%8C" title="مخابرات نوری – Persian" lang="fa" hreflang="fa" data-title="مخابرات نوری" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Communication_optique" title="Communication optique – French" lang="fr" hreflang="fr" data-title="Communication optique" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B4%91_%ED%86%B5%EC%8B%A0" title="광 통신 – Korean" lang="ko" hreflang="ko" data-title="광 통신" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%95%E0%A4%BE%E0%A4%B6%E0%A4%BF%E0%A4%95_%E0%A4%B8%E0%A4%82%E0%A4%9A%E0%A4%BE%E0%A4%B0" title="प्रकाशिक संचार – Hindi" lang="hi" hreflang="hi" data-title="प्रकाशिक संचार" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Komunikasi_optik" title="Komunikasi optik – Indonesian" lang="id" hreflang="id" data-title="Komunikasi optik" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Comunicazioni_ottiche" title="Comunicazioni ottiche – Italian" lang="it" hreflang="it" data-title="Comunicazioni ottiche" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%AA%D7%A7%D7%A9%D7%95%D7%A8%D7%AA_%D7%90%D7%95%D7%A4%D7%98%D7%99%D7%AA" title="תקשורת אופטית – Hebrew" lang="he" hreflang="he" data-title="תקשורת אופטית" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9E%D0%BF%D1%82%D0%B8%D0%BA%D0%B0%D0%BB%D1%8B%D2%9B_%D0%B1%D0%B0%D0%B9%D0%BB%D0%B0%D0%BD%D1%8B%D1%81" title="Оптикалық байланыс – Kazakh" lang="kk" hreflang="kk" data-title="Оптикалық байланыс" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Komunikasi_optik" title="Komunikasi optik – Malay" lang="ms" hreflang="ms" data-title="Komunikasi optik" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Optische_communicatie" title="Optische communicatie – Dutch" lang="nl" hreflang="nl" data-title="Optische communicatie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%85%89%E3%81%AB%E3%82%88%E3%82%8B%E9%80%9A%E4%BF%A1" title="光による通信 – Japanese" lang="ja" hreflang="ja" data-title="光による通信" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Optisk_kommunikasjon" title="Optisk kommunikasjon – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Optisk kommunikasjon" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Comunica%C3%A7%C3%A3o_%C3%B3ptica" title="Comunicação óptica – Portuguese" lang="pt" hreflang="pt" data-title="Comunicação óptica" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Opti%C4%8Dna_komunikacija" title="Optična komunikacija – Slovenian" lang="sl" hreflang="sl" data-title="Optična komunikacija" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Optisk_kommunikation" title="Optisk kommunikation – Swedish" lang="sv" hreflang="sv" data-title="Optisk kommunikation" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Optik_ileti%C5%9Fim" title="Optik iletişim – Turkish" lang="tr" hreflang="tr" data-title="Optik iletişim" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Th%C3%B4ng_tin_quang" title="Thông tin quang – Vietnamese" lang="vi" hreflang="vi" data-title="Thông tin quang" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%85%89%E9%80%9A%E8%A8%8A" title="光通訊 – Chinese" lang="zh" hreflang="zh" data-title="光通訊" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a 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dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Use of light to convey information</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_(MHC_61.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2b/US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg/220px-US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg" decoding="async" width="220" height="157" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2b/US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg/330px-US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2b/US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg/440px-US_Navy_020623-N-5329L-007_Signalman_2nd_Class_Eric_Palmer_signals_the_U.S._Navy_mine_hunter_coastal_ship_USS_Raven_%28MHC_61.jpg 2x" data-file-width="2100" data-file-height="1500" /></a><figcaption> A naval <a href="/wiki/Signal_lamp" title="Signal lamp">signal lamp</a>, a form of optical communication that uses shutters and is typically employed with <a href="/wiki/Morse_code" title="Morse code">Morse code</a> (2002)</figcaption></figure> <p><b>Optical communication</b>, also known as <b>optical telecommunication</b>, is <a href="/wiki/Communication" title="Communication">communication</a> at a distance using <a href="/wiki/Light" title="Light">light</a> to carry information. It can be performed visually or by using <a href="/wiki/Electronics" title="Electronics">electronic devices</a>. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the <a href="/wiki/Photophone" title="Photophone">photophone</a>, invented in 1880. </p><p>An optical <a href="/wiki/Communication_system" class="mw-redirect" title="Communication system">communication system</a> uses a <a href="/wiki/Transmitter" title="Transmitter">transmitter</a>, which encodes a <a href="/wiki/Message" title="Message">message</a> into an optical <a href="/wiki/Signal_(information_theory)" class="mw-redirect" title="Signal (information theory)">signal</a>, a <a href="/wiki/Communication_channel" title="Communication channel">channel</a>, which carries the signal to its destination, and a <a href="/wiki/Tuner_(radio)" title="Tuner (radio)">receiver</a>, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a <a href="/wiki/Beacon" title="Beacon">beacon fire</a>) or complex (such as lights using color codes or flashed in a <a href="/wiki/Morse_code" title="Morse code">Morse code</a> sequence). </p><p>Modern communication relies on optical networking systems using <a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a>, <a href="/wiki/Optical_amplifier" title="Optical amplifier">optical amplifiers</a>, <a href="/wiki/Laser" title="Laser">lasers</a>, switches, <a href="/wiki/Router_(computing)" title="Router (computing)">routers</a>, and other related technologies. <a href="/wiki/Free-space_optical_communication" class="mw-redirect" title="Free-space optical communication">Free-space optical communication</a> use lasers to transmit signals in space, while terrestrial forms are naturally limited by geography and weather. This article provides a basic introduction to different forms of optical communication. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Visual_forms">Visual forms</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=1" title="Edit section: Visual forms"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Visual techniques such as <a href="/wiki/Smoke_signals" class="mw-redirect" title="Smoke signals">smoke signals</a>, <a href="/wiki/Beacon" title="Beacon">beacon fires</a>, <a href="/wiki/Hydraulic_telegraph" title="Hydraulic telegraph">hydraulic telegraphs</a>, <a href="/wiki/Ship_flags" class="mw-redirect" title="Ship flags">ship flags</a> and <a href="/wiki/Semaphore_line" class="mw-redirect" title="Semaphore line">semaphore lines</a> were the earliest forms of optical communication.<sup id="cite_ref-Burns2004_1-0" class="reference"><a href="#cite_note-Burns2004-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-EncyBrit1824_2-0" class="reference"><a href="#cite_note-EncyBrit1824-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Hydraulic telegraph semaphores date back to the 4th century BCE Greece. <a href="/wiki/Distress_flare" class="mw-redirect" title="Distress flare">Distress flares</a> are still used by mariners in emergencies, while <a href="/wiki/Lighthouse" title="Lighthouse">lighthouses</a> and <a href="/wiki/Navigation_light" title="Navigation light">navigation lights</a> are used to communicate navigation hazards. </p><p>The <a href="/wiki/Heliograph" title="Heliograph">heliograph</a> uses a <a href="/wiki/Mirror" title="Mirror">mirror</a> to <a href="/wiki/Reflection_(physics)" title="Reflection (physics)">reflect</a> sunlight to a distant observer.<sup id="cite_ref-Boer_5-0" class="reference"><a href="#cite_note-Boer-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> When a signaler tilts the mirror to reflect sunlight, the distant observer sees flashes of light that can be used to transmit a prearranged signaling code. <a href="/wiki/Navy" title="Navy">Naval</a> <a href="/wiki/Ship" title="Ship">ships</a> often use <a href="/wiki/Signal_lamp" title="Signal lamp">signal lamps</a> and Morse code in a similar way. </p><p><a href="/wiki/Aviator" class="mw-redirect" title="Aviator">Aircraft pilots</a> often use <a href="/wiki/Visual_approach_slope_indicator" title="Visual approach slope indicator">visual approach slope indicator</a> (VASI) projected light systems to land safely, especially at night. Military aircraft landing on an <a href="/wiki/Aircraft_carrier" title="Aircraft carrier">aircraft carrier</a> use a similar system to land correctly on a carrier deck. The coloured light system communicates the aircraft's height relative to a standard landing <a href="/wiki/Glideslope" class="mw-redirect" title="Glideslope">glideslope</a>. As well, <a href="/wiki/Air_traffic_control#Airport_control" title="Air traffic control">airport control towers</a> still use <a href="/wiki/Aldis_lamp" class="mw-redirect" title="Aldis lamp">Aldis lamps</a> to transmit instructions to aircraft whose radios have failed. </p> <div class="mw-heading mw-heading3"><h3 id="Semaphore_line">Semaphore line</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=2" title="Edit section: Semaphore line"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraph</a></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:OptischerTelegraf.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/94/OptischerTelegraf.jpg/170px-OptischerTelegraf.jpg" decoding="async" width="170" height="227" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/94/OptischerTelegraf.jpg/255px-OptischerTelegraf.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/94/OptischerTelegraf.jpg/340px-OptischerTelegraf.jpg 2x" data-file-width="1200" data-file-height="1600" /></a><figcaption>A replica of a <a href="/wiki/Chappe_telegraph" title="Chappe telegraph">Chappe telegraph</a> tower (18th century)</figcaption></figure> <p>A 'semaphore telegraph', also called a 'semaphore line', 'optical telegraph', 'shutter telegraph chain', '<a href="/wiki/Chappe_telegraph" title="Chappe telegraph">Chappe telegraph</a>', or 'Napoleonic semaphore', is a system used for conveying information by means of visual signals, using towers with pivoting arms or shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position.<sup id="cite_ref-EncyBrit1824_2-1" class="reference"><a href="#cite_note-EncyBrit1824-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-EdEnc1832_6-0" class="reference"><a href="#cite_note-EdEnc1832-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>Semaphore lines were a precursor of the <a href="/wiki/Electrical_telegraph" title="Electrical telegraph">electrical telegraph</a>. They were far faster than <a href="/wiki/Post_rider" class="mw-redirect" title="Post rider">post riders</a> for conveying a message over long distances, but far more expensive and less private than the electrical telegraph lines which would later replace them. The maximum distance that a pair of semaphore telegraph stations can bridge is limited by geography, weather and the availability of light; thus, in practical use, most optical telegraphs used lines of relay stations to bridge longer distances. Each relay station would also require its complement of skilled operator-observers to convey messages back and forth across the line. </p><p>The modern design of semaphores was first foreseen by the British <a href="/wiki/Polymath" title="Polymath">polymath</a> <a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a>, who first gave a vivid and comprehensive outline of visual telegraphy in a 1684 submission to the <a href="/wiki/Royal_Society" title="Royal Society">Royal Society</a>. His proposal (which was motivated by military concerns following the <a href="/wiki/Battle_of_Vienna" title="Battle of Vienna">Battle of Vienna</a> the preceding year) was not put into practice during his lifetime.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>The first operational optical semaphore line arrived in 1792, created by the French engineer <a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a> and his brothers, who succeeded in covering <a href="/wiki/France" title="France">France</a> with a network of 556 stations stretching a total distance of 4,800 kilometres (3,000 mi). It was used for military and national communications until the 1850s. </p><p>Many national services adopted signaling systems different from the Chappe system. For example, <a href="/wiki/UK" class="mw-redirect" title="UK">Britain</a> and <a href="/wiki/Sweden" title="Sweden">Sweden</a> adopted systems of shuttered panels (in contradiction to the Chappe brothers' contention that angled rods are more visible). In <a href="/wiki/Spain" title="Spain">Spain</a>, the engineer <a href="/wiki/Agust%C3%ADn_de_Betancourt" title="Agustín de Betancourt">Agustín de Betancourt</a> developed his own system which was adopted by that state. This system was considered by many experts in Europe better than Chappe's, even in France.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (August 2023)">citation needed</span></a></i>]</sup> </p><p>These systems were popular in the late 18th to early 19th century but could not compete with the electrical telegraph, and went completely out of service by 1880.<sup id="cite_ref-Burns2004_1-1" class="reference"><a href="#cite_note-Burns2004-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Semaphore_signal_flags">Semaphore signal flags</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=3" title="Edit section: Semaphore signal flags"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Flag_semaphore" title="Flag semaphore">Flag semaphore</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:020118-N-6520M-011_Semaphore_Flags.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b2/020118-N-6520M-011_Semaphore_Flags.jpg/220px-020118-N-6520M-011_Semaphore_Flags.jpg" decoding="async" width="220" height="144" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b2/020118-N-6520M-011_Semaphore_Flags.jpg/330px-020118-N-6520M-011_Semaphore_Flags.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b2/020118-N-6520M-011_Semaphore_Flags.jpg/440px-020118-N-6520M-011_Semaphore_Flags.jpg 2x" data-file-width="2000" data-file-height="1312" /></a><figcaption>A naval signaler transmitting a message by flag semaphore (2002).</figcaption></figure> <p>Semaphore flags are the system for conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags, objects or arms; it is read when they are in a fixed position. </p><p>Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of <a href="/wiki/Semaphore_line" class="mw-redirect" title="Semaphore line">shutter semaphores</a>) in the maritime world in the 19th century. They are still used during <a href="/wiki/Underway_replenishment" title="Underway replenishment">underway replenishment at sea</a> and are acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night. </p><p>The newer flag semaphore system uses two short poles with square flags, which a signaler holds in different positions to convey letters of the alphabet and numbers. The transmitter holds one pole in each hand, and extends each arm in one of eight possible directions. Except for in the rest position, the flags cannot overlap. The flags are colored differently based on whether the signals are sent by sea or by land. At sea, the flags are colored red and yellow (the <a href="/wiki/International_maritime_signal_flags#Letters" title="International maritime signal flags">Oscar flags</a>), while on land, they are white and blue (the <a href="/wiki/International_maritime_signal_flags#Letters" title="International maritime signal flags">Papa flags</a>). Flags are not required, they just make the characters more obvious. </p> <div class="mw-heading mw-heading3"><h3 id="Signal_lamps">Signal lamps</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=4" title="Edit section: Signal lamps"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Signal_lamp" title="Signal lamp">Signal lamp</a> and <a href="/wiki/Aviation_light_signals" title="Aviation light signals">Aviation light signals</a></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:TC_with_light_gun.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ea/TC_with_light_gun.JPG/220px-TC_with_light_gun.JPG" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ea/TC_with_light_gun.JPG/330px-TC_with_light_gun.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ea/TC_with_light_gun.JPG/440px-TC_with_light_gun.JPG 2x" data-file-width="448" data-file-height="336" /></a><figcaption>An <a href="/wiki/Air_traffic_controller" title="Air traffic controller">air traffic controller</a> holding a signal light gun that can be used to direct aircraft experiencing a radio failure (2007).</figcaption></figure> <p>Signal lamps (such as Aldis lamps), are visual signaling devices for optical communication (typically using Morse code). Modern signal lamps are a focused lamp which can produce a pulse of light. In large versions this pulse is achieved by opening and closing shutters mounted in front of the lamp, either via a manually operated pressure switch or, in later versions, automatically. </p><p>With hand held lamps, a <a href="/wiki/Curved_mirror#Concave_mirrors" title="Curved mirror">concave mirror</a> is tilted by a trigger to focus the light into pulses. The lamps are usually equipped with some form of optical sight, and are most commonly deployed on naval vessels and also used in airport control towers with coded <a href="/wiki/Aviation_light_signals" title="Aviation light signals">aviation light signals</a>. </p><p><a href="/wiki/Aviation_light_signals" title="Aviation light signals">Aviation light signals</a> are used in the case of a <a href="/wiki/NORDO" title="NORDO">radio failure</a>, an <a href="/wiki/Aircraft" title="Aircraft">aircraft</a> not equipped with a radio, or in the case of a hearing-impaired pilot. <a href="/wiki/Air_traffic_controller" title="Air traffic controller">Air traffic controllers</a> have long used signal light guns to direct such aircraft. The light gun's lamp has a focused bright beam capable of emitting three different colors: red, white and green. These colors may be flashing or steady, and provide different instructions to aircraft in flight or on the ground (for example, "cleared to land" or "cleared for takeoff"). Pilots can acknowledge the instructions by wiggling their plane's wings, moving their <a href="/wiki/Aileron" title="Aileron">ailerons</a> if they are on the ground, or by flashing their <a href="/wiki/Aircraft_landing_lights" class="mw-redirect" title="Aircraft landing lights">landing</a> or <a href="/wiki/Navigation_light" title="Navigation light">navigation lights</a> during night time. Only 12 simple standardized instructions are directed at aircraft using signal light guns as the system is not utilized with Morse code. </p> <div class="mw-heading mw-heading3"><h3 id="Heliograph">Heliograph</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=5" title="Edit section: Heliograph"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Australian_Heliograph_in_Egyptian_Desert_1940.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Australian_Heliograph_in_Egyptian_Desert_1940.png/250px-Australian_Heliograph_in_Egyptian_Desert_1940.png" decoding="async" width="170" height="240" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Australian_Heliograph_in_Egyptian_Desert_1940.png/330px-Australian_Heliograph_in_Egyptian_Desert_1940.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/67/Australian_Heliograph_in_Egyptian_Desert_1940.png/500px-Australian_Heliograph_in_Egyptian_Desert_1940.png 2x" data-file-width="3534" data-file-height="4993" /></a><figcaption>Heliograph: Australians using a heliograph in North Africa (1940).</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Heliograph" title="Heliograph">Heliograph</a></div> <p>A heliograph (<a href="/wiki/Greek_language" title="Greek language">Greek</a>: <span lang="el">Ἥλιος</span> <i><a href="/wiki/Helios" title="Helios">helios</a></i>, meaning "sun", and <span title="Greek-language text"><span lang="el">γραφειν</span></span> <i><a href="https://en.wiktionary.org/wiki/-graphy" class="extiw" title="wikt:-graphy">graphein</a></i>, meaning "write") is a wireless solar <a href="/wiki/Telegraph" class="mw-redirect" title="Telegraph">telegraph</a> that signals by flashes of <a href="/wiki/Sunlight" title="Sunlight">sunlight</a> (generally using Morse code) reflected by a <a href="/wiki/Mirror" title="Mirror">mirror</a>. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. </p><p>The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were in military, surveys and forest protection work. They were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975.<sup id="cite_ref-Boer_5-1" class="reference"><a href="#cite_note-Boer-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Electronic_forms">Electronic forms</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=6" title="Edit section: Electronic forms"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the present day a variety of electronic systems optically transmit and receive information carried by pulses of light. <a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> cables are employed to carry electronic data and telephone traffic. <a href="/wiki/Free-space_optical_communication" class="mw-redirect" title="Free-space optical communication">Free-space optical communications</a> are also used every day in various applications. </p> <div class="mw-heading mw-heading3"><h3 id="Optical_fiber">Optical fiber</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=7" title="Edit section: Optical fiber"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a></div> <p>Optical fiber is the most common type of channel for optical communications. The transmitters in optical fiber links are generally <a href="/wiki/Light-emitting_diode" title="Light-emitting diode">light-emitting diodes</a> (LEDs) or <a href="/wiki/Laser_diode" title="Laser diode">laser diodes</a>. <a href="/wiki/Infrared" title="Infrared">Infrared</a> light is used more commonly than <a href="/wiki/Visible_light" class="mw-redirect" title="Visible light">visible light</a>, because optical fibers transmit infrared wavelengths with less <a href="/wiki/Attenuation_(electromagnetic_radiation)" class="mw-redirect" title="Attenuation (electromagnetic radiation)">attenuation</a> and <a href="/wiki/Dispersion_(optics)" title="Dispersion (optics)">dispersion</a>. The signal encoding is typically simple <a href="/wiki/Intensity_modulation" title="Intensity modulation">intensity modulation</a>, although historically optical phase and <a href="/wiki/Frequency_modulation" title="Frequency modulation">frequency modulation</a> have been demonstrated in the lab. The need for periodic <a href="/wiki/Signal_regeneration" title="Signal regeneration">signal regeneration</a> was largely superseded by the introduction of the <a href="/wiki/Erbium-doped_fiber_amplifier" class="mw-redirect" title="Erbium-doped fiber amplifier">erbium-doped fiber amplifier</a>, which extended link distances at significantly lower cost. The commercial introduction of dense <a href="/wiki/Wavelength-division_multiplexing" title="Wavelength-division multiplexing">wavelength-division multiplexing</a> (WDM) in 1996 by <a href="/wiki/Ciena" title="Ciena">Ciena Corp</a> was the real start of optical networking.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> WDM is now the common basis of nearly every high-capacity optical system in the world.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p><p>The first optical communication systems were designed and delivered to the U.S. Army and Chevron by Optelecom, Inc.,<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> the venture co-founded by Gordon Gould, the inventor of the optical amplifier<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> and the laser.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Photophone">Photophone</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=8" title="Edit section: Photophone"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Photophone" title="Photophone">Photophone</a></div> <p>The photophone (originally given an alternate name, <a href="/wiki/Radiophone" class="mw-redirect" title="Radiophone">radiophone</a>) is a communication device which allowed for the <a href="/wiki/Transmission_(telecommunications)" class="mw-redirect" title="Transmission (telecommunications)">transmission</a> of speech on a beam of <a href="/wiki/Light" title="Light">light</a>. It was invented jointly by <a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a> and his assistant <a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a> on February 19, 1880, at Bell's 1325 'L' Street laboratory in Washington, D.C.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-SDU_16-0" class="reference"><a href="#cite_note-SDU-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Both were later to become full associates in the <a href="/wiki/Volta_Laboratory_and_Bureau#Laboratory_projects" title="Volta Laboratory and Bureau">Volta Laboratory Association</a>, created and financed by Bell. </p><p>On June 21, 1880, Bell's assistant transmitted a wireless voice telephone message of considerable distance, from the roof of the <a href="/wiki/Franklin_School_(Washington,_D.C.)" title="Franklin School (Washington, D.C.)">Franklin School</a> to the window of Bell's laboratory, some 213 meters (about 700 ft) away.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Carson-2007-gvttw_18-0" class="reference"><a href="#cite_note-Carson-2007-gvttw-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Groth_19-0" class="reference"><a href="#cite_note-Groth-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Mims_1982,_p._11_20-0" class="reference"><a href="#cite_note-Mims_1982,_p._11-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p>Bell believed the photophone was his most important <a href="/wiki/Invention" title="Invention">invention</a>. Of the 18 <a href="/wiki/Patent" title="Patent">patents</a> granted in Bell's name alone, and the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention [I have] ever made, greater than the telephone".<sup id="cite_ref-Mims_1982,_p._14_21-0" class="reference"><a href="#cite_note-Mims_1982,_p._14-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p><p>The photophone was a precursor to the <a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">fiber-optic communication</a> systems which achieved popular worldwide usage starting in the 1980s.<sup id="cite_ref-Morgan_22-0" class="reference"><a href="#cite_note-Morgan-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AmericanScientist-1984.V72.No1_23-0" class="reference"><a href="#cite_note-AmericanScientist-1984.V72.No1-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Gallardo+Mims_24-0" class="reference"><a href="#cite_note-Gallardo+Mims-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> The master patent for the photophone (<span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US235199">U.S. patent 235,199</a></span> <i>Apparatus for Signalling and Communicating, called Photophone</i>), was issued in December 1880,<sup id="cite_ref-Groth_19-1" class="reference"><a href="#cite_note-Groth-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> many decades before its principles came to have practical applications. </p> <div class="mw-heading mw-heading3"><h3 id="Free-space_optical_communication">Free-space optical communication</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=9" title="Edit section: Free-space optical communication"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951" /><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Free-space_optical_communication" class="mw-redirect" title="Free-space optical communication">Free-space optical communication</a> and <a href="/wiki/Optical_wireless_communications" title="Optical wireless communications">Optical wireless communications</a></div> <p>Free-space optics (FSO) systems are employed for '<a href="/wiki/Last_mile_(telecommunications)" title="Last mile (telecommunications)">last mile</a>' <a href="/wiki/Telecommunications" title="Telecommunications">telecommunications</a> and can function over distances of several kilometers as long as there is a clear <a href="/wiki/Line-of-sight_propagation" title="Line-of-sight propagation">line of sight</a> between the source and the destination, and the optical receiver can reliably decode the transmitted information.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> Other free-space systems can provide high-data-rate, long-range links using small, low-mass, low-power-consumption subsystems which make them suitable for communications in space.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> Various planned <a href="/wiki/Satellite_constellation" title="Satellite constellation">satellite constellations</a> intended to provide global broadband coverage take advantage of these benefits and employ <a href="/wiki/Laser_communication_in_space" title="Laser communication in space">laser communication</a> for inter-satellite links between the several hundred to thousand satellites effectively creating a space-based <a href="/wiki/Optical_mesh_network" title="Optical mesh network">optical mesh network</a>. </p><p>More generally, transmission of unguided optical signals is known as <a href="/wiki/Optical_wireless_communications" title="Optical wireless communications">optical wireless communications</a> (OWC). Examples include medium-range <a href="/wiki/Visible_light_communication" title="Visible light communication">visible light communication</a> and short-distance <a href="/wiki/Infrared_Data_Association" title="Infrared Data Association">IrDA</a>, using infrared LEDs. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=10" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 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title="commons:Category:Optical communication">Optical communication</a></span>.</div></div> </div> <ul><li><a href="/wiki/Fiber_tapping" title="Fiber tapping">Fiber tapping</a></li> <li><a href="/wiki/Interconnect_bottleneck" title="Interconnect bottleneck">Interconnect bottleneck</a></li> <li><a href="/wiki/Jun-Ichi_Nishizawa" class="mw-redirect" title="Jun-Ichi Nishizawa">Jun-Ichi Nishizawa</a> an inventor of optical communication.</li> <li><a href="/wiki/Modulating_retro-reflector" title="Modulating retro-reflector">Modulating retro-reflector</a></li> <li><a href="/wiki/OECC" title="OECC">OECC</a> (OptoElectronics and Communications Conference)</li> <li><a href="/wiki/Optical_interconnect" title="Optical interconnect">Optical interconnect</a></li> <li><a href="/wiki/Opto-isolator" title="Opto-isolator">Opto-isolator</a></li> <li><a href="/wiki/Parallel_optical_interface" title="Parallel optical interface">Parallel optical interface</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=11" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Citations">Citations</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=12" title="Edit section: Citations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width reflist-columns-2"> <ol class="references"> <li id="cite_note-Burns2004-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Burns2004_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Burns2004_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=7eUUy8-VvwoC&pg=PA29">Chapter 2: Semaphore Signalling</a> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-86341-327-8" title="Special:BookSources/978-0-86341-327-8">978-0-86341-327-8</a> Communications: an international history of the formative years R. W. Burns, 2004</span> </li> <li id="cite_note-EncyBrit1824-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-EncyBrit1824_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-EncyBrit1824_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=MsYnAAAAMAAJ&pg=PA645">Telegraph</a> Vol 10, Encyclopædia Britannica, 6th Edition, 1824 pp. 645-651</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.nps.gov/fire/utility/uti_tl_perspectivestext.cfm">"Nation Park Service Fire History Timeline"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Nation+Park+Service+Fire+History+Timeline&rft_id=http%3A%2F%2Fwww.nps.gov%2Ffire%2Futility%2Futi_tl_perspectivestext.cfm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://lewisandclarkjournals.unl.edu/read/?_xmlsrc=1805-07-20.xml&_xslsrc=LCstyles.xsl">"Lewis and Clark Journals, July 20, 1805"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Lewis+and+Clark+Journals%2C+July+20%2C+1805&rft_id=http%3A%2F%2Flewisandclarkjournals.unl.edu%2Fread%2F%3F_xmlsrc%3D1805-07-20.xml%26_xslsrc%3DLCstyles.xsl&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-Boer-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-Boer_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Boer_5-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Harris, J.D. <a rel="nofollow" class="external text" href="http://rapidttp.com/milhist/vol111jh.html">Wire At War – Signals communication in the South African War 1899–1902</a>. Retrieved on 1 June 2008. Note a discussion on the heliograph use during the Boer War.</span> </li> <li id="cite_note-EdEnc1832-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-EdEnc1832_6-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=VhEbAQAAMAAJ&pg=PA657">Telegraph</a>, Volume 17 of The Edinburgh encyclopaedia, pp. 664–667, 1832 David Brewster, ed.</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Calvert, J.B. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120208081932/http://mysite.du.edu/~jcalvert/railway/semaphor/semhist.htm">The Origin of the Railway Semaphore</a>, <a href="/wiki/Boston_University" title="Boston University">Boston University</a>, 15 April 2000, Revised 4 May 2007.</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text">McVeigh, Daniel P. <a rel="nofollow" class="external text" href="http://www.ilt.columbia.edu/projects/bluetelephone/html/part2.html">An Early History of the Telephone: 1664-1865, Part 2</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20121128120005/http://www.ilt.columbia.edu/projects/bluetelephone/html/part2.html">Archived</a> 2012-11-28 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, <a href="/wiki/Columbia_University" title="Columbia University">Columbia University in The City of New York</a>, Institute For Learning Technologies, 2000.</span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFMarkoff1997" class="citation news cs1">Markoff, John (1997-03-03). <a rel="nofollow" class="external text" href="https://www.nytimes.com/1997/03/03/business/fiber-optic-technology-draws-record-stock-value.html">"Fiber-Optic Technology Draws Record Stock Value"</a>. <i>The New York Times</i>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0362-4331">0362-4331</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2021-11-08</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=Fiber-Optic+Technology+Draws+Record+Stock+Value&rft.date=1997-03-03&rft.issn=0362-4331&rft.aulast=Markoff&rft.aufirst=John&rft_id=https%3A%2F%2Fwww.nytimes.com%2F1997%2F03%2F03%2Fbusiness%2Ffiber-optic-technology-draws-record-stock-value.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFCvijetic2013" class="citation book cs1">Cvijetic, Milorad (2013). <i>Advanced optical communication systems and networks</i>. Ivan Djordjevic. 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Wiley; 1st edition. p. 2.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Wavelength+Division+Multiplexing%3A+A+Practical+Engineering+Guide+%28Wiley+Series+in+Pure+and+Applied+Optics%29&rft.pages=2&rft.pub=Wiley%3B+1st+edition&rft.date=2013&rft.aulast=Grobe&rft.aufirst=Klaus&rft.au=Eiselt%2C+Michael&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFNick2019" class="citation book cs1">Nick, Taylor (2019). <i>Laser: The Inventor the Nobel Laureate and the Thirty-Year Patent War</i>. Jonas Street Books. p. 226.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Laser%3A+The+Inventor+the+Nobel+Laureate+and+the+Thirty-Year+Patent+War&rft.pages=226&rft.pub=Jonas+Street+Books&rft.date=2019&rft.aulast=Nick&rft.aufirst=Taylor&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFNick2019" class="citation book cs1">Nick, Taylor (2019). <i>Laser: The Inventor the Nobel Laureate and the Thirty-Year Patent War</i>. Jones Street Books. p. 212.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Laser%3A+The+Inventor+the+Nobel+Laureate+and+the+Thirty-Year+Patent+War&rft.pages=212&rft.pub=Jones+Street+Books&rft.date=2019&rft.aulast=Nick&rft.aufirst=Taylor&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFNick2019" class="citation book cs1">Nick, Taylor (2019). <i>Laser: The Inventor the Nobel Laureate and the Thirty-Year Patent War</i>. 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Retrieved from the University of San Diego History Department website, November 26, 2009.</span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text">Bruce 1990, pg. 338</span> </li> <li id="cite_note-Carson-2007-gvttw-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-Carson-2007-gvttw_18-0">^</a></b></span> <span class="reference-text">Carson 2007, pg. 76-78</span> </li> <li id="cite_note-Groth-19"><span class="mw-cite-backlink">^ <a href="#cite_ref-Groth_19-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Groth_19-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Groth, Mike. <a rel="nofollow" class="external text" href="http://www.bluehaze.com.au/modlight/GrothArticle1.htm">Photophones Revisted</a>, 'Amateur Radio' magazine, <a href="/wiki/Wireless_Institute_of_Australia" title="Wireless Institute of Australia">Wireless Institute of Australia</a>, Melbourne, April 1987 pp. 12–17 and May 1987 pp. 13–17.</span> </li> <li id="cite_note-Mims_1982,_p._11-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-Mims_1982,_p._11_20-0">^</a></b></span> <span class="reference-text">Mims 1982, p. 11.</span> </li> <li id="cite_note-Mims_1982,_p._14-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-Mims_1982,_p._14_21-0">^</a></b></span> <span class="reference-text">Mims 1982, p. 14.</span> </li> <li id="cite_note-Morgan-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-Morgan_22-0">^</a></b></span> <span class="reference-text">Morgan, Tim J. "The Fiber Optic Backbone", <a href="/wiki/University_of_North_Texas" title="University of North Texas">University of North Texas</a>, 2011.</span> </li> <li id="cite_note-AmericanScientist-1984.V72.No1-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-AmericanScientist-1984.V72.No1_23-0">^</a></b></span> <span class="reference-text">Miller, Stewart E. "Lightwaves and Telecommunication", <i><a href="/wiki/American_Scientist" title="American Scientist">American Scientist</a></i>, Sigma Xi, The Scientific Research Society, January–February 1984, Vol. 72, No. 1, pp. 66-71, <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/i27852430">Issue Stable URL</a>.</span> </li> <li id="cite_note-Gallardo+Mims-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-Gallardo+Mims_24-0">^</a></b></span> <span class="reference-text">Gallardo, Arturo; <a href="/wiki/Forrest_Mims" title="Forrest Mims">Mims III, Forrest M.</a> <a rel="nofollow" class="external text" href="http://www.mysanantonio.com/default/article/Fiber-optic-communication-began-130-years-ago-783469.php">Fiber-optic Communication Began 130 Years Ago</a>, <i><a href="/wiki/San_Antonio_Express-News" title="San Antonio Express-News">San Antonio Express-News</a></i>, June 21, 2010. Accessed January 1, 2013.</span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFClint_Turner2007" class="citation web cs1">Clint Turner (October 3, 2007). <a rel="nofollow" class="external text" href="http://www.modulatedlight.org/optical_comms/optical_qso_173mile.html">"A 173-mile 2-way all-electronic optical contact"</a>. <i>Modulated light web site</i><span class="reference-accessdate">. Retrieved <span class="nowrap">June 28,</span> 2011</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Modulated+light+web+site&rft.atitle=A+173-mile+2-way+all-electronic+optical+contact&rft.date=2007-10-03&rft.au=Clint+Turner&rft_id=http%3A%2F%2Fwww.modulatedlight.org%2Foptical_comms%2Foptical_qso_173mile.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFWilson2000" class="citation report cs1">Wilson, K. (2000-01-04). Recent Development in High-Data Rate Optical Communications at JPL. <i>Jet Propulsion Laboratory</i> (Report). <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://hdl.handle.net/2014%2F18156">2014/18156</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=report&rft.btitle=Recent+Development+in+High-Data+Rate+Optical+Communications+at+JPL&rft.date=2000-01-04&rft_id=info%3Ahdl%2F2014%2F18156&rft.aulast=Wilson&rft.aufirst=K.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></span> </li> </ol></div> <div class="mw-heading mw-heading3"><h3 id="Bibliography">Bibliography</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=13" title="Edit section: Bibliography"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin refbegin-columns references-column-width" style="column-width: 30em"> <ul><li>Alwayn, Vivek. <a rel="nofollow" class="external text" href="http://www.ciscopress.com/articles/article.asp?p=170740&seqNum=1&rl=1">Fiber-Optic Technologies</a>, Cisco Press, Apr 23, 2004.</li> <li><a href="/wiki/List_of_Boston_University_people#Guggenheim_Fellows" title="List of Boston University people">Bruce, Robert V</a> <i>Bell: Alexander Bell and the Conquest of Solitude</i>, Ithaca, New York: <a href="/wiki/Cornell_University" title="Cornell University">Cornell University Press</a>, 1990. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-8014-9691-8" title="Special:BookSources/0-8014-9691-8">0-8014-9691-8</a>.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFCarson2007" class="citation book cs1">Carson, Mary Kay (2007). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/alexandergrahamb0000cars"><i>Alexander Graham Bell: Giving Voice To The World</i></a></span>. Sterling Biographies. New York: Sterling Publishing Co., Inc. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/alexandergrahamb0000cars/page/76">76</a>–78. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4027-3230-0" title="Special:BookSources/978-1-4027-3230-0"><bdi>978-1-4027-3230-0</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/182527281">182527281</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Alexander+Graham+Bell%3A+Giving+Voice+To+The+World&rft.place=New+York&rft.series=Sterling+Biographies&rft.pages=76-78&rft.pub=Sterling+Publishing+Co.%2C+Inc.&rft.date=2007&rft_id=info%3Aoclcnum%2F182527281&rft.isbn=978-1-4027-3230-0&rft.aulast=Carson&rft.aufirst=Mary+Kay&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Falexandergrahamb0000cars&rfr_id=info%3Asid%2Fen.wikipedia.org%3AOptical+communication" class="Z3988"></span></li> <li><a href="/wiki/Forrest_Mims" title="Forrest Mims">Mims III, Forest M</a>. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=zoaSp1BJu50C&pg=PA1">The First Century of Lightwave Communications</a>, <i>Fiber Optics Weekly Update</i>, Information Gatekeepers, February 10–26, 1982, pp. 6–23.</li> <li>Paschotta, Rüdiger. <a rel="nofollow" class="external text" href="https://www.rp-photonics.com/optical_fiber_communications.html">Encyclopedia of Laser Physics and Technology</a>, RP-Photonics.com website, 2012.</li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Optical_communication&action=edit&section=14" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Polina_Bayvel" title="Polina Bayvel">Bayvel, Polina</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/discover/10.2307/2666790">Future High-Capacity Optical Telecommunication Networks</a>, <i>Philosophical Transactions: Mathematical, Physical and Engineering Sciences</i>, Vol. 358, No. 1765, January 2000, Science into the Next Millennium: Young Scientists Give Their Visions of the Future: II. Mathematics, Physics and Engineering, pp. 303–329, stable article URL: <a rel="nofollow" class="external free" href="https://www.jstor.org/stable/2666790">https://www.jstor.org/stable/2666790</a>, published by <a href="/wiki/The_Royal_Society" class="mw-redirect" title="The Royal Society">The Royal Society</a>.</li> <li>Dilhac, J-M. <a rel="nofollow" class="external text" href="http://www.ieeeghn.org/wiki/images/1/17/Dilhac.pdf">The Telegraph of Claude Chappe -An Optical Telecommunication Network For The XVIII Century</a>, Toulouse: Institut National des Sciences Appliquées de Toulouse. 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telecommunication</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Basic</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signal</a></li> <li><a href="/wiki/Beacon" title="Beacon">Beacon</a></li> <li><a href="/wiki/Hydraulic_telegraph" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/International_maritime_signal_flags" title="International maritime signal flags">Ships' flags</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraph</a></li> <li><a href="/wiki/Heliograph" title="Heliograph">Heliograph</a></li> <li><a href="/wiki/Signal_lamp" title="Signal lamp">Signal lamp</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Advanced</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optics</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">Optical fiber</a> <ul><li><a href="/wiki/Fiber-optic_cable" title="Fiber-optic cable">Cable</a></li> <li><a href="/wiki/Optical_fiber_connector" title="Optical fiber connector">Connectors</a></li></ul></li></ul></li> <li><a href="/wiki/Optical_wireless_communications" title="Optical wireless communications">Optical wireless</a> <ul><li><a href="/wiki/Free-space_optical_communication" class="mw-redirect" title="Free-space optical communication">Free-space</a></li> <li><a href="/wiki/Visible_light_communication" title="Visible light communication">Visible light</a></li> <li><a href="/wiki/Li-Fi" title="Li-Fi">Li-Fi</a></li> <li><a href="/wiki/Laser_communication_in_space" title="Laser communication in space">In space</a></li> <li><a href="/wiki/Consumer_IR" title="Consumer IR">Consumer IR</a></li></ul></li> <li><a href="/wiki/Optical_Transport_Network" class="mw-redirect" title="Optical Transport Network">Optical Transport Network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technologies</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Optical_Carrier_transmission_rates" title="Optical Carrier transmission rates">OC Rates</a></li> <li><a href="/wiki/Intensity_modulation" title="Intensity modulation">Intensity modulation</a></li> <li><a href="/wiki/Modulating_retro-reflector" title="Modulating retro-reflector">Modulating retro-reflector</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="font-weight:bold;"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" 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navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beacon#For_defensive_communications" title="Beacon">Beacon</a></li> <li><a href="/wiki/History_of_broadcasting" title="History of broadcasting">Broadcasting</a></li> <li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Cable_television" title="Cable television">Cable TV</a></li> <li><a href="/wiki/Communications_satellite#History" title="Communications satellite">Communications satellite</a></li> <li><a href="/wiki/Computer_network#History" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a> <ul><li><a href="/wiki/Audio_coding_format" title="Audio coding format">audio</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Image_compression" title="Image compression">image</a></li> <li><a href="/wiki/Video_coding_format" title="Video coding format">video</a></li></ul></li> <li><a href="/wiki/Digital_media" title="Digital media">Digital media</a> <ul><li><a href="/wiki/Internet_video" title="Internet video">Internet video</a></li> <li><a href="/wiki/Online_video_platform" title="Online video platform">online video platform</a></li> <li><a href="/wiki/Social_media" title="Social media">social media</a></li> <li><a href="/wiki/Streaming_media" title="Streaming media">streaming</a></li></ul></li> <li><a href="/wiki/Drums_in_communication" title="Drums in communication">Drums</a></li> <li><a href="/wiki/Edholm%27s_law" title="Edholm's law">Edholm's law</a></li> <li><a href="/wiki/Electrical_telegraph#History" title="Electrical telegraph">Electrical telegraph</a></li> <li><a href="/wiki/Fax#History" title="Fax">Fax</a></li> <li><a href="/wiki/Heliograph#History" title="Heliograph">Heliographs</a></li> <li><a href="/wiki/Hydraulic_telegraph#Greek_hydraulic_semaphore_system" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/Information_Age" title="Information Age">Information Age</a></li> <li><a href="/wiki/Information_revolution" class="mw-redirect" title="Information revolution">Information revolution</a></li> <li><a href="/wiki/History_of_the_Internet" title="History of the Internet">Internet</a></li> <li><a href="/wiki/Mass_media#History" title="Mass media">Mass media</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">Mobile phone</a> <ul><li><a href="/wiki/Smartphone" title="Smartphone">Smartphone</a></li></ul></li> <li><a class="mw-selflink selflink">Optical telecommunication</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraphy</a></li> <li><a href="/wiki/Pager" title="Pager">Pager</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li> <li><a href="/wiki/History_of_prepaid_mobile_phones" title="History of prepaid mobile phones">Prepaid mobile phone</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">Radio</a></li> <li><a href="/wiki/Radiotelephone" title="Radiotelephone">Radiotelephone</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Satellite communications</a></li> <li><a href="/wiki/Semaphore" title="Semaphore">Semaphore</a> <ul><li><a href="/wiki/Phryctoria" title="Phryctoria">Phryctoria</a></li></ul></li> <li><a href="/wiki/Semiconductor" title="Semiconductor">Semiconductor</a> <ul><li><a href="/wiki/Semiconductor_device" title="Semiconductor device">device</a></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a></li> <li><a href="/wiki/History_of_the_transistor" title="History of the transistor">transistor</a></li></ul></li> <li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signals</a></li> <li><a href="/wiki/History_of_telecommunication" title="History of telecommunication">Telecommunications history</a></li> <li><a href="/wiki/Telautograph" title="Telautograph">Telautograph</a></li> <li><a href="/wiki/Telegraphy" title="Telegraphy">Telegraphy</a></li> <li><a href="/wiki/Teleprinter" title="Teleprinter">Teleprinter</a> (teletype)</li> <li><a href="/wiki/History_of_the_telephone" title="History of the telephone">Telephone</a></li> <li><i><a href="/wiki/The_Telephone_Cases" title="The Telephone Cases">The Telephone Cases</a></i></li> <li><a href="/wiki/History_of_television" title="History of television">Television</a> <ul><li><a href="/wiki/Digital_television" title="Digital television">digital</a></li> <li><a href="/wiki/Streaming_television" title="Streaming television">streaming</a></li></ul></li> <li><a href="/wiki/Submarine_communications_cable#Early_history:_telegraph_and_coaxial_cables" title="Submarine communications cable">Undersea telegraph line</a></li> <li><a href="/wiki/History_of_videotelephony" title="History of videotelephony">Videotelephony</a></li> <li><a href="/wiki/Whistled_language" title="Whistled language">Whistled language</a></li> <li><a href="/wiki/Wireless_revolution" class="mw-redirect" title="Wireless revolution">Wireless revolution</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pioneers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nasir_Ahmed_(engineer)" title="Nasir Ahmed (engineer)">Nasir Ahmed</a></li> <li><a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin Howard Armstrong</a></li> <li><a href="/wiki/Mohamed_M._Atalla" title="Mohamed M. Atalla">Mohamed M. Atalla</a></li> <li><a href="/wiki/John_Logie_Baird" title="John Logie Baird">John Logie Baird</a></li> <li><a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a></li> <li><a href="/wiki/John_Bardeen" title="John Bardeen">John Bardeen</a></li> <li><a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a></li> <li><a href="/wiki/Emile_Berliner" title="Emile Berliner">Emile Berliner</a></li> <li><a href="/wiki/Tim_Berners-Lee" title="Tim Berners-Lee">Tim Berners-Lee</a></li> <li><a href="/wiki/Francis_Blake_(inventor)" title="Francis Blake (inventor)">Francis Blake</a></li> <li><a href="/wiki/Jagadish_Chandra_Bose" title="Jagadish Chandra Bose">Jagadish Chandra Bose</a></li> <li><a href="/wiki/Charles_Bourseul" title="Charles Bourseul">Charles Bourseul</a></li> <li><a href="/wiki/Walter_Houser_Brattain" title="Walter Houser Brattain">Walter Houser Brattain</a></li> <li><a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a></li> <li><a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a></li> <li><a href="/wiki/Yogen_Dalal" class="mw-redirect" title="Yogen Dalal">Yogen Dalal</a></li> <li><a href="/wiki/Donald_Davies" title="Donald Davies">Donald Davies</a></li> <li><a href="/wiki/Daniel_Davis_Jr." title="Daniel Davis Jr.">Daniel Davis Jr.</a></li> <li><a href="/wiki/Amos_Dolbear" title="Amos Dolbear">Amos Dolbear</a></li> <li><a href="/wiki/Thomas_Edison" title="Thomas Edison">Thomas Edison</a></li> <li><a href="/wiki/Philo_Farnsworth" title="Philo Farnsworth">Philo Farnsworth</a></li> <li><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></li> <li><a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a></li> <li><a href="/wiki/Elisha_Gray" title="Elisha Gray">Elisha Gray</a></li> <li><a href="/wiki/Oliver_Heaviside" title="Oliver Heaviside">Oliver Heaviside</a></li> <li><a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a></li> <li><a href="/wiki/Erna_Schneider_Hoover" title="Erna Schneider Hoover">Erna Schneider Hoover</a></li> <li><a href="/wiki/Harold_Hopkins_(physicist)" title="Harold Hopkins (physicist)">Harold Hopkins</a></li> <li><a href="/wiki/Gardiner_Greene_Hubbard" title="Gardiner Greene Hubbard">Gardiner Greene Hubbard</a></li> <li><a href="/wiki/Bob_Kahn" class="mw-redirect" title="Bob Kahn">Bob Kahn</a></li> <li><a href="/wiki/Dawon_Kahng" title="Dawon Kahng">Dawon Kahng</a></li> <li><a href="/wiki/Charles_K._Kao" title="Charles K. Kao">Charles K. Kao</a></li> <li><a href="/wiki/Narinder_Singh_Kapany" title="Narinder Singh Kapany">Narinder Singh Kapany</a></li> <li><a href="/wiki/Hedy_Lamarr" title="Hedy Lamarr">Hedy Lamarr</a></li> <li><a href="/wiki/Roberto_Landell_de_Moura" title="Roberto Landell de Moura">Roberto Landell</a></li> <li><a href="/wiki/Innocenzo_Manzetti" title="Innocenzo Manzetti">Innocenzo Manzetti</a></li> <li><a href="/wiki/Guglielmo_Marconi" title="Guglielmo Marconi">Guglielmo Marconi</a></li> <li><a href="/wiki/Robert_Metcalfe" title="Robert Metcalfe">Robert Metcalfe</a></li> <li><a href="/wiki/Antonio_Meucci" title="Antonio Meucci">Antonio Meucci</a></li> <li><a href="/wiki/Samuel_Morse" title="Samuel Morse">Samuel Morse</a></li> <li><a href="/wiki/Jun-ichi_Nishizawa" title="Jun-ichi Nishizawa">Jun-ichi Nishizawa</a></li> <li><a href="/wiki/Charles_Grafton_Page" title="Charles Grafton Page">Charles Grafton Page</a></li> <li><a href="/wiki/Radia_Perlman" title="Radia Perlman">Radia Perlman</a></li> <li><a href="/wiki/Alexander_Stepanovich_Popov" class="mw-redirect" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a></li> <li><a href="/wiki/Tivadar_Pusk%C3%A1s" title="Tivadar Puskás">Tivadar Puskás</a></li> <li><a href="/wiki/Johann_Philipp_Reis" title="Johann Philipp Reis">Johann Philipp Reis</a></li> <li><a href="/wiki/Claude_Shannon" title="Claude Shannon">Claude Shannon</a></li> <li><a href="/wiki/Almon_Brown_Strowger" title="Almon Brown Strowger">Almon Brown Strowger</a></li> <li><a href="/wiki/Henry_Sutton_(inventor)" title="Henry Sutton (inventor)">Henry Sutton</a></li> <li><a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a></li> <li><a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a></li> <li><a href="/wiki/Camille_Tissot" title="Camille Tissot">Camille Tissot</a></li> <li><a href="/wiki/Alfred_Vail" title="Alfred Vail">Alfred Vail</a></li> <li><a href="/wiki/Thomas_A._Watson" title="Thomas A. Watson">Thomas A. Watson</a></li> <li><a href="/wiki/Charles_Wheatstone" title="Charles Wheatstone">Charles Wheatstone</a></li> <li><a href="/wiki/Vladimir_K._Zworykin" title="Vladimir K. Zworykin">Vladimir K. Zworykin</a></li> <li><i><a href="/wiki/List_of_Internet_pioneers" title="List of Internet pioneers">Internet pioneers</a></i></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transmission_medium" title="Transmission medium">Transmission<br />media</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coaxial_cable" title="Coaxial cable">Coaxial cable</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a></li></ul></li> <li><a href="/wiki/Free-space_optical_communication" class="mw-redirect" title="Free-space optical communication">Free-space optical communication</a></li> <li><a href="/wiki/Molecular_communication" title="Molecular communication">Molecular communication</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio waves</a> <ul><li><a href="/wiki/Wireless" title="Wireless">wireless</a></li></ul></li> <li><a href="/wiki/Transmission_line" title="Transmission line">Transmission line</a> <ul><li><a href="/wiki/Telecommunication_circuit" title="Telecommunication circuit">telecommunication circuit</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_topology" title="Network topology">Network topology</a><br />and switching</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">Bandwidth</a></li> <li><a href="/wiki/Telecommunications_link" title="Telecommunications link">Links</a></li> <li><a href="/wiki/Network_switch" title="Network switch">Network switching</a> <ul><li><a href="/wiki/Circuit_switching" title="Circuit switching">circuit</a></li> <li><a href="/wiki/Packet_switching" title="Packet switching">packet</a></li></ul></li> <li><a href="/wiki/Node_(networking)" title="Node (networking)">Nodes</a> <ul><li><a href="/wiki/Terminal_(telecommunication)" title="Terminal (telecommunication)">terminal</a></li></ul></li> <li><a href="/wiki/Telephone_exchange" title="Telephone exchange">Telephone exchange</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">Space-division</a></li> <li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division</a></li> <li><a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">Time-division</a></li> <li><a href="/wiki/Polarization-division_multiplexing" title="Polarization-division multiplexing">Polarization-division</a></li> <li><a href="/wiki/Orbital_angular_momentum_multiplexing" title="Orbital angular momentum multiplexing">Orbital angular-momentum</a></li> <li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">Code-division</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></li> <li><a href="/wiki/Computer_network" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_communication" title="Data communication">Data transmission</a></li> <li><a href="/wiki/Store_and_forward" title="Store and forward">Store and forward</a></li> <li><a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">Telecommunications equipment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Types of network</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Local_area_network" title="Local area network">LAN</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile</a></li> <li><a href="/wiki/Next-generation_network" title="Next-generation network">NGN</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">Public Switched Telephone</a></li> <li><a href="/wiki/Radio_network" title="Radio network">Radio</a></li> <li><a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">Television</a></li> <li><a href="/wiki/Telex" title="Telex">Telex</a></li> <li><a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li><a href="/wiki/Wide_area_network" title="Wide area network">WAN</a></li> <li><a href="/wiki/Wireless_network" title="Wireless network">Wireless network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Notable networks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a></li> <li><a href="/wiki/BITNET" title="BITNET">BITNET</a></li> <li><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Internet" title="Internet">Internet</a></li> <li><a href="/wiki/Internet2" title="Internet2">Internet2</a></li> <li><a href="/wiki/JANET" title="JANET">JANET</a></li> <li><a href="/wiki/NPL_network" title="NPL network">NPL network</a></li> <li><a href="/wiki/Toasternet" title="Toasternet">Toasternet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Locations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:Telecommunications_in_Africa" title="Category:Telecommunications in Africa">Africa</a></li> <li>Americas <ul><li><a href="/wiki/Category:Telecommunications_in_North_America" title="Category:Telecommunications in North America">North</a></li> <li><a href="/wiki/Category:Telecommunications_in_South_America" title="Category:Telecommunications in South America">South</a></li></ul></li> <li><a href="/wiki/Category:Communications_in_Antarctica" title="Category:Communications in Antarctica">Antarctica</a></li> <li><a href="/wiki/Category:Telecommunications_in_Asia" title="Category:Telecommunications in Asia">Asia</a></li> <li><a href="/wiki/Category:Telecommunications_in_Europe" title="Category:Telecommunications in Europe">Europe</a></li> <li><a href="/wiki/Category:Telecommunications_in_Oceania" title="Category:Telecommunications in Oceania">Oceania</a></li> <li><i><a href="/wiki/List_of_telecommunications_regulatory_bodies" title="List of telecommunications regulatory bodies">Global telecommunications regulation bodies</a></i></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/15px-Telecom-icon.svg.png" decoding="async" width="15" height="15" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/23px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/30px-Telecom-icon.svg.png 2x" data-file-width="500" data-file-height="500" /></span></span> </span><a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Telecommunications" title="Category:Telecommunications">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="List-Class article"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Outline_of_telecommunication" title="Outline of telecommunication">Outline</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/20px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span> <a href="https://commons.wikimedia.org/wiki/Category:Telecommunications" class="extiw" title="commons:Category:Telecommunications">Commons</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output .tooltip-dotted{border-bottom:1px dotted;cursor:help}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1038841319" /></div><div role="navigation" class="navbox authority-control" aria-label="Navbox961" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q1469765#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 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