{"id":252,"date":"2022-11-28T19:26:59","date_gmt":"2022-11-28T19:26:59","guid":{"rendered":"http:\/\/learnlearn.uk\/ibcs\/?page_id=252"},"modified":"2022-11-28T19:26:59","modified_gmt":"2022-11-28T19:26:59","slug":"optical-data-transmission","status":"publish","type":"page","link":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/","title":{"rendered":"Optical Data Transmission"},"content":{"rendered":"<div class=\"responsive-tabs\">\n<h2 class=\"tabtitle\">Intro<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Introduction to Optical Data Transmission<\/h3>\n<div id=\"attachment_275\" style=\"width: 310px\" class=\"wp-caption alignright\"><img aria-describedby=\"caption-attachment-275\" decoding=\"async\" loading=\"lazy\" class=\"size-medium wp-image-275\" src=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/great-wall-towers-300x200.jpg\" alt=\"\" width=\"300\" height=\"200\" \/><p id=\"caption-attachment-275\" class=\"wp-caption-text\"><a href=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/10\/20090529_Great_Wall_8185.jpg\/800px-20090529_Great_Wall_8185.jpg\">Great Wall of China signal towers. Source: Wikipedia<\/a><\/p><\/div>\n<p>Using light to transmit signals is nothing new. Signal fires and smoke signals have been used for thousands of years. Because light travels incredibly fast signals could be sent from place to place very quickly.<\/p>\n<p>Native Americans and other cultures used smoke signals and the Chinese signal tower system along the Great wall of China allowed warnings of potential invasion by the Mongolians to be sent back to the government long distances of up to 500km in day.<\/p>\n<p>Ships also used semaphore signals and signal lamps to send Morse code between ships in visible distance of each other.<\/p>\n<p>As the limitations of electrical data transmission became apparent in the middle of the 20th century, research into the alternatives began. By 1977 the first telephone traffic was being routed through a fiber optic connection.<\/p>\n\n<\/div><h2 class=\"tabtitle\">Fiber Optics<\/h2>\n<div class=\"tabcontent\">\n\n<h3>How Fiber Optics Works<\/h3>\n<div id=\"attachment_273\" style=\"width: 310px\" class=\"wp-caption alignright\"><img aria-describedby=\"caption-attachment-273\" decoding=\"async\" loading=\"lazy\" class=\"size-medium wp-image-273\" src=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/Fiber_optic_illuminated-300x188.jpg\" alt=\"\" width=\"300\" height=\"188\" \/><p id=\"caption-attachment-273\" class=\"wp-caption-text\"><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Fiber_optic_illuminated.jpg\">Source: Wikipedia<\/a><\/p><\/div>\n<p>Fiber optics works by send light along glass fiber cables. Data is sent in binary pulses using laser light and the light travels from one end of the cable to the other, bouncing along the internal of the cable through a physics phenomenon known as <strong>total internal reflection<\/strong>.<\/p>\n<p>Multiple light signals using different wavelengths can be sent at the same time, which allows for higher bandwidth and full duplex transmission &#8211; this is known as <strong>multiplexing<\/strong>.<\/p>\n<p>The current maximum bandwidth for fiber optical cables is 10 GB\/s.<\/p>\n<p>Due to total internal reflection the cables do not suffer with\u00a0<strong>interference<\/strong> or <strong>crosstalk<\/strong>\u00a0and s<strong>ignal degradation<\/strong> over a much greater distance when compared to electrical cables.<\/p>\n<div id=\"attachment_284\" style=\"width: 505px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/total-internal-reflection.png\"><img aria-describedby=\"caption-attachment-284\" decoding=\"async\" loading=\"lazy\" class=\"wp-image-284 \" src=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/total-internal-reflection.png?_t=1620179554\" alt=\"\" width=\"495\" height=\"171\" \/><\/a><p id=\"caption-attachment-284\" class=\"wp-caption-text\">Total Internal Reflection. <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Optic_fibre-numerical_aperture_diagram.svg\">Source: Wikipedia<\/a><\/p><\/div>\n<h3><\/h3>\n\n<\/div><h2 class=\"tabtitle\">Video<\/h2>\n<div class=\"tabcontent\">\n\n<h3>How Fiber Optics Works &#8211; Video<\/h3>\n<div class=\"nv-iframe-embed\">\n<div class=\"container-lazyload preview-lazyload container-youtube js-lazyload--not-loaded\"><a href=\"https:\/\/www.youtube.com\/watch?v=0MwMkBET_5I\" class=\"lazy-load-youtube preview-lazyload preview-youtube\" data-video-title=\"Fiber optic cables: How they work\" title=\"Play video &quot;Fiber optic cables: How they work&quot;\">https:\/\/www.youtube.com\/watch?v=0MwMkBET_5I<\/a><noscript>Video can&#8217;t be loaded because JavaScript is disabled: <a href=\"https:\/\/www.youtube.com\/watch?v=0MwMkBET_5I\" title=\"Fiber optic cables: How they work\">Fiber optic cables: How they work (https:\/\/www.youtube.com\/watch?v=0MwMkBET_5I)<\/a><\/noscript><\/div>\n<\/div>\n<p>&nbsp;<\/p>\n\n<\/div><h2 class=\"tabtitle\">Undersea Cables<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Fiber Optic Undersea Cables<\/h3>\n<div id=\"attachment_274\" style=\"width: 310px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/2\/22\/African_undersea_cables_v44.jpg\"><img aria-describedby=\"caption-attachment-274\" decoding=\"async\" loading=\"lazy\" class=\"wp-image-274 size-medium\" src=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/africa-undersea-fibre-optical-cable-networks-300x284.jpg\" alt=\"\" width=\"300\" height=\"284\" \/><\/a><p id=\"caption-attachment-274\" class=\"wp-caption-text\">African and European undersea cables. Source: Wikipedia<\/p><\/div>\n<p>Fiber optical cables now form the backbone of international internet networks, handling most global traffic. Fiber optic cables and can handle huge amounts of data compared to cable networks and have the advantage of only requiring signals to be booster <a href=\"https:\/\/www.submarinenetworks.com\/en\/insights\/next-generation-submarine-network-innovative-repeater-technology\">every 100km underwater using a repeater.<\/a>\u00a0Fiber optic cables are still vulnerable to damage, especially from shark attacks and <a href=\"https:\/\/www.bbc.com\/news\/world-africa-17179544\">ship anchors<\/a>.<\/p>\n<p>&nbsp;<\/p>\n\n<\/div><h2 class=\"tabtitle\">Pros &amp; Cons<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Advantages of Fiber Optic<\/h3>\n<ul>\n<li>More data can be sent per cable, meaning much higher bandwidth than through electrical cables<\/li>\n<li>The glass cables don&#8217;t corrode as easily as copper cables<\/li>\n<li>Reduced signal degradation means that fewer repeaters are required for long distance transmission and there it is cheaper at scale<\/li>\n<li>Fiber optic cables are more secure than copper cables as you have to break the cable to eaves drop.<\/li>\n<\/ul>\n<h3>Disadvantages of Fiber Optic cables<\/h3>\n<ul>\n<li>Fiber optic networking devices are currently more expensive than ethernet devices<\/li>\n<li>The cables are more fragile than ethernet cables in home networks.<\/li>\n<li>Fiber optic networking devices are less common than ethernet and therefore aren&#8217;t compatible with most exisiting networking devices<\/li>\n<\/ul>\n\n<\/div><h2 class=\"tabtitle\">Li-Fi<\/h2>\n<div class=\"tabcontent\">\n\n<p><em>Note: Li-fi is not currently mentioned on the iGCSE specification but it&#8217;s an interesting technology so I&#8217;m adding it here!<\/em><\/p>\n<h3>Limitations of Wifi<\/h3>\n<p>Wi-fi networking in homes and offices is incredibly popular, however it does have a number of disdvantages:<\/p>\n<ul>\n<li>Interference between different networks, especially in apartment blocks, is becoming a increasing problem.<\/li>\n<li>Wi-fi is limited in the spectrum it can use and there has a limited maximum transmission speed.<\/li>\n<li>It is also not very secure and easy to hack because the <a href=\"https:\/\/www.wired.com\/story\/russian-spies-indictment-hotel-wi-fi-hacking\/\">signals leak outside of the building<\/a>.<\/li>\n<\/ul>\n<p>This has meant that alternatives to radio based wireless networks are being developed. One such technology is Li-Fi.<\/p>\n<h3>Li-Fi Networking<\/h3>\n<p>Li-Fi is a technology where data is sent using light from the invisible portion of the spectrum (usually ultraviolet light). This has a number of advantages over Wi-fi as there is no interference between different networks and it is easier to ensure network security by making windows opaque.<\/p>\n<p>It also has a number of <a href=\"https:\/\/en.wikipedia.org\/wiki\/Li-Fi\">advantages in special use areas.<\/a><\/p>\n<p><a href=\"https:\/\/www.ted.com\/talks\/harald_haas_wireless_data_from_every_light_bulb\">See the TED talk introducing Li-Fi here<\/a><\/p>\n\n<\/div><h2 class=\"tabtitle\">Quiz<\/h2>\n<div class=\"tabcontent\">\n\n<p><iframe loading=\"lazy\" src=\"https:\/\/docs.google.com\/forms\/d\/e\/1FAIpQLSeIVGbn9qkIoQU3kYq2hNHSKmbM5xa4JOYZd0-pEpNYm4C0fA\/viewform?embedded=true\" width=\"900\" height=\"600\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" data-mce-fragment=\"1\">Loading\u2026<\/iframe><\/p>\n\n<\/div><h2 class=\"tabtitle\">Resources<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Resources<\/h3>\n<p><a href=\"https:\/\/docs.google.com\/presentation\/d\/19seZZsLPoXbOm0MDc20E2xsKwm-GgyMNMeaGYBZaoCI\/edit?usp=sharing\">Pupil Research Task<\/a><\/p>\n<p><a href=\"https:\/\/quizizz.com\/admin\/quiz\/584843d3b0511bf07a201c4f\">Quizizz<\/a><\/p>\n<p><a href=\"https:\/\/docs.google.com\/presentation\/d\/1VwF9yvGtAZYiYKcsyP9SXwyxVwJvPMO6j-2kgpMrYMg\/edit?usp=sharing\">Lesson Presentation<\/a><\/p>\n<h3>Past Paper Questions<\/h3>\n<p>I couldn&#8217;t find any so yeah&#8230;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<\/div><\/div>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Introduction to Optical Data Transmission Using light to transmit signals is nothing new. Signal fires and smoke signals have been used for thousands of years. Because light travels incredibly fast signals could be sent from place to place very quickly. Native Americans and other cultures used smoke signals and the Chinese signal tower system along&hellip;&nbsp;<a href=\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\" class=\"\" rel=\"bookmark\">Read More &raquo;<span class=\"screen-reader-text\">Optical Data Transmission<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":70,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":""},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Optical Data Transmission - IB Computer Science<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Optical Data Transmission - IB Computer Science\" \/>\n<meta property=\"og:description\" content=\"Introduction to Optical Data Transmission Using light to transmit signals is nothing new. Signal fires and smoke signals have been used for thousands of years. Because light travels incredibly fast signals could be sent from place to place very quickly. Native Americans and other cultures used smoke signals and the Chinese signal tower system along&hellip;&nbsp;Read More &raquo;Optical Data Transmission\" \/>\n<meta property=\"og:url\" content=\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\" \/>\n<meta property=\"og:site_name\" content=\"IB Computer Science\" \/>\n<meta property=\"og:image\" content=\"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/great-wall-towers-300x200.jpg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\",\"url\":\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\",\"name\":\"Optical Data Transmission - IB Computer Science\",\"isPartOf\":{\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#website\"},\"datePublished\":\"2022-11-28T19:26:59+00:00\",\"dateModified\":\"2022-11-28T19:26:59+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/#breadcrumb\"},\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"IB Computer Science\",\"item\":\"https:\/\/learnlearn.uk\/ibcs\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Optical Data Transmission\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#website\",\"url\":\"https:\/\/learnlearn.uk\/ibcs\/\",\"name\":\"IB Computer Science\",\"description\":\"- learnlearn..uk\",\"publisher\":{\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/learnlearn.uk\/ibcs\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-GB\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#organization\",\"name\":\"IB Computer Science\",\"url\":\"https:\/\/learnlearn.uk\/ibcs\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/learnlearn.uk\/ibcs\/wp-content\/uploads\/sites\/25\/2022\/09\/LearnLearnLogowhite-300x41.png\",\"contentUrl\":\"https:\/\/learnlearn.uk\/ibcs\/wp-content\/uploads\/sites\/25\/2022\/09\/LearnLearnLogowhite-300x41.png\",\"width\":300,\"height\":41,\"caption\":\"IB Computer Science\"},\"image\":{\"@id\":\"https:\/\/learnlearn.uk\/ibcs\/#\/schema\/logo\/image\/\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Optical Data Transmission - IB Computer Science","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/","og_locale":"en_GB","og_type":"article","og_title":"Optical Data Transmission - IB Computer Science","og_description":"Introduction to Optical Data Transmission Using light to transmit signals is nothing new. Signal fires and smoke signals have been used for thousands of years. Because light travels incredibly fast signals could be sent from place to place very quickly. Native Americans and other cultures used smoke signals and the Chinese signal tower system along&hellip;&nbsp;Read More &raquo;Optical Data Transmission","og_url":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/","og_site_name":"IB Computer Science","og_image":[{"url":"https:\/\/learnlearn.uk\/igcsecs\/wp-content\/uploads\/sites\/23\/2021\/05\/great-wall-towers-300x200.jpg"}],"twitter_card":"summary_large_image","twitter_misc":{"Estimated reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/","url":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/","name":"Optical Data Transmission - IB Computer Science","isPartOf":{"@id":"https:\/\/learnlearn.uk\/ibcs\/#website"},"datePublished":"2022-11-28T19:26:59+00:00","dateModified":"2022-11-28T19:26:59+00:00","breadcrumb":{"@id":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/learnlearn.uk\/ibcs\/optical-data-transmission\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"IB Computer Science","item":"https:\/\/learnlearn.uk\/ibcs\/"},{"@type":"ListItem","position":2,"name":"Optical Data Transmission"}]},{"@type":"WebSite","@id":"https:\/\/learnlearn.uk\/ibcs\/#website","url":"https:\/\/learnlearn.uk\/ibcs\/","name":"IB Computer Science","description":"- learnlearn..uk","publisher":{"@id":"https:\/\/learnlearn.uk\/ibcs\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/learnlearn.uk\/ibcs\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-GB"},{"@type":"Organization","@id":"https:\/\/learnlearn.uk\/ibcs\/#organization","name":"IB Computer Science","url":"https:\/\/learnlearn.uk\/ibcs\/","logo":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/learnlearn.uk\/ibcs\/#\/schema\/logo\/image\/","url":"https:\/\/learnlearn.uk\/ibcs\/wp-content\/uploads\/sites\/25\/2022\/09\/LearnLearnLogowhite-300x41.png","contentUrl":"https:\/\/learnlearn.uk\/ibcs\/wp-content\/uploads\/sites\/25\/2022\/09\/LearnLearnLogowhite-300x41.png","width":300,"height":41,"caption":"IB Computer Science"},"image":{"@id":"https:\/\/learnlearn.uk\/ibcs\/#\/schema\/logo\/image\/"}}]}},"rttpg_featured_image_url":null,"rttpg_author":{"display_name":"learnlearnadmin","author_link":"https:\/\/learnlearn.uk\/ibcs\/author\/learnlearnadmin\/"},"rttpg_comment":0,"rttpg_category":null,"rttpg_excerpt":"Introduction to Optical Data Transmission Using light to transmit signals is nothing new. Signal fires and smoke signals have been used for thousands of years. Because light travels incredibly fast signals could be sent from place to place very quickly. Native Americans and other cultures used smoke signals and the Chinese signal tower system along&hellip;&nbsp;Read&hellip;","_links":{"self":[{"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/pages\/252"}],"collection":[{"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/comments?post=252"}],"version-history":[{"count":1,"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/pages\/252\/revisions"}],"predecessor-version":[{"id":254,"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/pages\/252\/revisions\/254"}],"wp:attachment":[{"href":"https:\/\/learnlearn.uk\/ibcs\/wp-json\/wp\/v2\/media?parent=252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}