{"id":966,"date":"2019-06-04T16:01:22","date_gmt":"2019-06-04T16:01:22","guid":{"rendered":"https:\/\/labsites.wdev.rochester.edu\/agrawal\/?page_id=966"},"modified":"2020-12-17T19:59:25","modified_gmt":"2020-12-17T19:59:25","slug":"optical-communications","status":"publish","type":"page","link":"https:\/\/labsites.rochester.edu\/agrawal\/current-research\/optical-communications\/","title":{"rendered":"Optical Communications"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\"><strong><span class=\"has-inline-color has-vivid-purple-color\">Space-Division Multiplexing<\/span><\/strong><\/h2>\n\n\n\n<p>Multimode and multicore fibers are attracting attention for enhancing the capacity of optical communication systems through a new type of multiplexing known as the mode-division or space-division multiplexing (SDM). A NSF-funded project in my group (grant ECCS-1505636) has focused on studying the nonlinear effects inside multimode\/multicore fibers and study their impact on the performance of SDM systems. The figure below shows the SDM scheme schematically.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"630\" height=\"305\" src=\"https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/sdm1.png\" alt=\"\" class=\"wp-image-15032\" srcset=\"https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/sdm1.png 630w, https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/sdm1-300x145.png 300w\" sizes=\"auto, (max-width: 630px) 100vw, 630px\" \/><figcaption>Schematic of the SDM technique. A spatial multiplexer is used to combine several WDM signals and launch them into different cores or modes of an optical fiber. Source: G. P> Agrawal, Fiber-Optic Communication Systems, 5th ed. (Wiley, 2021)<\/figcaption><\/figure><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong><span class=\"has-inline-color has-vivid-purple-color\">Simulations for Multicore SDM systems<\/span><\/strong><\/h2>\n\n\n\n<p>In a 2014 study, numerical simulations were used to include both the linear and nonlinear<br>couplings among the cores of a multicore fiber. The simulated 1000-km-long SDM system transmitted 114-Gb\/s symbol streams through each core in the QPSK format with polarization-division multiplexing (PDM).  Digital signal processing was used at the receiving end to remove all linear impairments. Figure  shows the calculated bit-error rate (BER) as a function of optical signal-to-noise ratio (OSNR) for fibers up to 19 cores. The increase in the OSNR at a fixed BER is called the OSNR penalty.  The results indicated that linear coupling between the cores of a MCF actually improves the performance of a MCF-based SDM system. Experiments have confirmed this prediction.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"777\" src=\"https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/osnr1-1024x777.jpg\" alt=\"\" class=\"wp-image-15042\" srcset=\"https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/osnr1-1024x777.jpg 1024w, https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/osnr1-300x228.jpg 300w, https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/osnr1-768x583.jpg 768w, https:\/\/labsites.rochester.edu\/agrawal\/wp-content\/uploads\/2020\/12\/osnr1.jpg 1435w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><figcaption>Computed bit-error rate (BER) as a function of Optical SNR for a multicore SDM system showing a reduced power penalty as the number of core increases. Source: IEEE Photonics Society Summer Topical Meetings,<br>2014, DOI: 10.1109\/SUM.2014.96.<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">For a list of recent publications, visit our&nbsp;<a href=\"https:\/\/labsites.rochester.edu\/agrawal\/publications\/\">publications page<\/a>.<\/h3>\n","protected":false},"excerpt":{"rendered":"<p>Space-Division Multiplexing Multimode and multicore fibers are attracting attention for enhancing the capacity of optical communication systems through a new type of multiplexing known as the mode-division or space-division multiplexing (SDM). A NSF-funded project in my group (grant ECCS-1505636) has focused on studying the nonlinear effects inside multimode\/multicore fibers and study their impact on the &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/labsites.rochester.edu\/agrawal\/current-research\/optical-communications\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Optical Communications&#8221;<\/span><\/a><\/p>\n","protected":false},"author":0,"featured_media":0,"parent":646,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-966","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/pages\/966","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/types\/page"}],"replies":[{"embeddable":true,"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/comments?post=966"}],"version-history":[{"count":3,"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/pages\/966\/revisions"}],"predecessor-version":[{"id":15062,"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/pages\/966\/revisions\/15062"}],"up":[{"embeddable":true,"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/pages\/646"}],"wp:attachment":[{"href":"https:\/\/labsites.rochester.edu\/agrawal\/wp-json\/wp\/v2\/media?parent=966"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}