{"id":4969,"date":"2025-05-09T18:00:00","date_gmt":"2025-05-09T09:00:00","guid":{"rendered":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/?page_id=4969"},"modified":"2025-05-11T22:58:31","modified_gmt":"2025-05-11T13:58:31","slug":"research-topics","status":"publish","type":"page","link":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/?page_id=4969&lang=en","title":{"rendered":"Research topics"},"content":{"rendered":"\n<p style=\"display: none;\">Recent research topics in this lab. are introduced\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000<\/p>\n<span id=\"page_top\">\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>List of Research Topics (Click to expand)<\/summary>\n<ol class=\"wp-block-list\">\n<li><a href=\"#topic1\">MDL Equalization Technology Using Long-Period Fiber Grating<\/a><\/li>\n<\/ol>\n<\/details>\n\n\n\n<div style=\"height:40px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"topic1\">MDL Equalization Technology Using Long-Period Fiber Grating<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"562\" src=\"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-1024x562.png\" alt=\"\" class=\"wp-image-4972\" srcset=\"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-1024x562.png 1024w, https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-300x165.png 300w, https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-768x421.png 768w, https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-1536x842.png 1536w, https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/wp-content\/uploads\/2025\/05\/\u4e00\u679a\u7d75_v5_E-2048x1123.png 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Mode division multiplexing (MDM) is attracting attention as one of the optical fiber communication technologies to address the explosive growth in data traffic. This technology enables simultaneous transmission of multiple optical signals through a single optical fiber by utilizing different propagation modes. However, higher-order modes are more susceptible to signal attenuation, and the variation in signal intensity between modes (Mode Dependent Loss: MDL) has been a limiting factor in communication performance by complicating signal processing.<\/p>\n\n\n\n<p>To solve this challenge, our laboratory is developing MDL equalization devices using Long Period Fiber Gratings (LPFG). By forming periodic refractive index changes (gratings) in the fiber core, LPFG enables mode coupling between the information-carrying &#8220;core modes&#8221; and the high-loss &#8220;cladding modes,&#8221; allowing for loss control. The figure below illustrates an example of MDL equalization: \u2460 Two core modes with different signal intensities are input (LP<sub>01<\/sub>: 100%, LP<sub>11<\/sub>: 50%). \u2461 In the grating section, part of the LP<sub>01<\/sub> core mode couples with the cladding mode, reducing the LP<sub>01<\/sub> core mode signal intensity. \u2462 As a result, the signal intensities of the two core modes (LP<sub>01 <\/sub>and LP<sub>11<\/sub>) become equal (50%) at the output.<\/p>\n\n\n\n<p>This technology is expected to contribute to the realization of future high-speed, large-capacity communication networks by enabling flexible and high-quality mode division multiplexed transmission.<\/p>\n\n\n\n<p><\/p>\n\n\n\n<a href=\"#page_top\" class=\"page_top_btn\">Page TOP<\/a>\n","protected":false},"excerpt":{"rendered":"<p>Recent research topics in this lab. are introduced\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000\u3000 MDL Equalization Technology Using Lon [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4969","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/pages\/4969","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4969"}],"version-history":[{"count":4,"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/pages\/4969\/revisions"}],"predecessor-version":[{"id":5017,"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=\/wp\/v2\/pages\/4969\/revisions\/5017"}],"wp:attachment":[{"href":"https:\/\/www.ist.hokudai.ac.jp\/labo\/photonics\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4969"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}