{"id":2244,"date":"2026-04-07T10:16:57","date_gmt":"2026-04-07T08:16:57","guid":{"rendered":"https:\/\/www.milq.info\/?page_id=2244"},"modified":"2026-04-07T12:41:31","modified_gmt":"2026-04-07T10:41:31","slug":"chapter2","status":"publish","type":"page","link":"https:\/\/www.milq.info\/en\/qti\/qcomm\/module3\/chapter2\/","title":{"rendered":"Quantum Communication &#8211; Module 3 Chapter 2"},"content":{"rendered":"<div id=\"bsf_rt_marker\"><\/div><p><\/p>\n<h1>Quantum Links<\/h1>\n<p><video src=\"\/QTIndu\/QComm\/en-3-2-video-1.mp4\" controls=\"controls\" width=\"1920\" height=\"150\"> Dein Browser unterst\u00fctzt dieses Videoformat nicht. Your browser does not support the video tag. <\/video><\/p>\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-120\" class=\"h5p-iframe\" data-content-id=\"120\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"QTI-EN-QComm-3-2-1\"><\/iframe><\/div>\n<hr \/>\n<p>The video showed a highly simplified excerpt of a possible quantum network. This excerpt will accompany us throughout the module and serves as a guide. The video introduced various types of quantum links\u2014optical-fiber links and free-space links.<\/p>\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-122\" class=\"h5p-iframe\" data-content-id=\"122\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"QTI-EN-QComm-3-2-2\"><\/iframe><\/div>\n<hr \/>\n<h2>Optical-fiber links<\/h2>\n<p>Optical-fiber links\u2014such as glass fiber\u2014are central to quantum networks because they ensure highly precise transmission of photonic qubits over long distances. They employ ultra-low-loss fibers and state-of-the-art technologies to minimize photon loss and maintain the coherence of quantum states. Optical fibers are ideal for urban networks and provide a scalable solution for expanding quantum-communication capacities in metropolitan regions. By exploiting the properties of light, they enable secure and efficient transmission of quantum information even in densely populated areas.<\/p>\n<hr \/>\n<h2>Free-space links<\/h2>\n<p>Free-space links enable quantum communication in the vacuum of space or in Earth\u2019s atmosphere. They are indispensable for satellite-based quantum networks and secure communication over intercontinental distances. Current developments, such as the experiments with the satellite \u201cMicius,\u201d have demonstrated the feasibility of space-based quantum key distribution and thus highlighted the potential for a global quantum-communication network. Free-space links are especially useful for connecting remote or hard-to-reach regions. They offer a flexible and scalable way to extend the reach of quantum networks beyond the limits of terrestrial infrastructure.<\/p>\n<hr \/>\n<h2>Challenges of quantum links<\/h2>\n<p>Establishing quantum links comes with considerable technological hurdles. To overcome them we need innovative solutions such as ultra-low-loss fibers, quantum repeaters (see Chapter 1), and advanced photonic technologies that ensure reliable transmission of quantum states over great distances. The central challenges are:<\/p>\n<p><video src=\"\/QTIndu\/QComm\/en-3-2-video-2.mp4\" controls=\"controls\" width=\"1920\" height=\"150\"> Dein Browser unterst\u00fctzt dieses Videoformat nicht. Your browser does not support the video tag. <\/video><\/p>\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-124\" class=\"h5p-iframe\" data-content-id=\"124\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"QTI-EN-QComm-3-2-3\"><\/iframe><\/div>\n<hr \/>\n<p>In summary, quantum networks represent a profound advance in communication technology. By harnessing quantum-mechanical principles, they offer unprecedented security and efficiency. A solid understanding of network architecture, the roles of quantum links and nodes, and current developments is essential for assessing the potential impact of this technology on various industries. However, it must always be borne in mind that numerous technical challenges complicate and delay implementation. Despite these obstacles, quantum networks will revolutionize the way we transmit, process, and store information and pave the way for a new era of technological innovations.<\/p>\n<hr \/>\n<h2>Exercises<\/h2>\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-126\" class=\"h5p-iframe\" data-content-id=\"126\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"QTI-EN-QComm-3-2-4\"><\/iframe><\/div>\n<p style=\"text-align: right;\"><a href=\"https:\/\/www.milq.info\/en\/qti\/qcomm\/module3\/chapter3\/\" class=button>Continue to Chapter 3<\/a><\/p>\n<p><\/p>","protected":false},"excerpt":{"rendered":"<p>Quantum Links Dein Browser unterst\u00fctzt dieses Videoformat nicht. Your browser does not support the video tag. The video showed a highly simplified excerpt of a possible quantum network. This excerpt will accompany us throughout the module and serves as a guide. The video introduced various types of quantum links\u2014optical-fiber links and free-space links. Optical-fiber links&hellip; <a href=\"https:\/\/www.milq.info\/en\/qti\/qcomm\/module3\/chapter2\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Quantum Communication &#8211; Module 3 Chapter 2<\/span><\/a><\/p>\n","protected":false},"author":8,"featured_media":0,"parent":2232,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2244","page","type-page","status-publish","hentry","without-featured-image"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Quantum Communication - Module 3 Chapter 2 - milq<\/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:\/\/www.milq.info\/qti\/qcomm\/module3\/chapter2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Quantum Communication - Module 3 Chapter 2 - milq\" \/>\n<meta property=\"og:description\" content=\"Quantum Links Dein Browser unterst\u00fctzt dieses Videoformat nicht. Your browser does not support the video tag. The video showed a highly simplified excerpt of a possible quantum network. This excerpt will accompany us throughout the module and serves as a guide. The video introduced various types of quantum links\u2014optical-fiber links and free-space links. 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