{"id":75221,"date":"2025-08-23T08:52:04","date_gmt":"2025-08-23T06:52:04","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=75221"},"modified":"2025-09-23T08:53:33","modified_gmt":"2025-09-23T06:53:33","slug":"these-feukam-takoundjou-09-10-2025-guides-donde-a-base-de-gaas-a-basse-temperature-vers-un-modulateur-electro-optique-integre-pour-le-moyen-infrarouge","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/a-la-une\/these-feukam-takoundjou-09-10-2025-guides-donde-a-base-de-gaas-a-basse-temperature-vers-un-modulateur-electro-optique-integre-pour-le-moyen-infrarouge.html","title":{"rendered":"THESE : Feukam TAKOUNDJOU &#8211; 09\/10\/2025 &#8211; Guides d\u2019onde \u00e0 base de GaAs \u00e0 basse temp\u00e9rature : vers un modulateur \u00e9lectro-optique int\u00e9gr\u00e9 pour le moyen infrarouge"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_heading  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_58_10tlc4wds7v8r\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 0px;\"><div class=\"ls-slide\" data-ls=\"duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-705x73.jpg 705w\" sizes=\"auto, (max-width: 2600px) 100vw, 2600px\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;border-style:solid;border-color:#000;background-position:0% 0%;background-repeat:no-repeat;width:180px;height:30px;left:0px;top:231px;line-height:32px;color:#ffffff;border-radius:6px 6px 6px 6px;padding-left:50px;background-color:rgba(0, 0, 0, 0.57);\" class=\"ls-l ls-ib-icon ls-text-layer\" data-ls=\"minfontsize:0;minmobilefontsize:0;\"><i class=\"fa fa-quote-right\" style=\"color:#ffffff;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>ACTUALITES<\/ls-layer><\/div><\/div><\/div><div id='after_layer_slider_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-75221'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k5dohoxw-286e18bc191b096bda1e0d08f538f47e\">\n#top .av-special-heading.av-k5dohoxw-286e18bc191b096bda1e0d08f538f47e{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-k5dohoxw-286e18bc191b096bda1e0d08f538f47e .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-k5dohoxw-286e18bc191b096bda1e0d08f538f47e .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-k5dohoxw-286e18bc191b096bda1e0d08f538f47e av-special-heading-h2  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first  av-linked-heading'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >THESE : Feukam TAKOUNDJOU &#8211; Guides d\u2019onde \u00e0 base de GaAs \u00e0 basse temp\u00e9rature : vers un modulateur \u00e9lectro-optique int\u00e9gr\u00e9 pour le moyen infrarouge <\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-18u73nj-dad6a947580930e400fc42ba200e80f1\">\n#top .hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1{\nmargin-top:5px;\nmargin-bottom:5px;\n}\n.hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1 .hr-inner{\nwidth:100%;\n}\n<\/style>\n<div  class='hr av-18u73nj-dad6a947580930e400fc42ba200e80f1 hr-custom  avia-builder-el-2  el_after_av_heading  el_before_av_textblock  hr-left hr-icon-no'><span class='hr-inner inner-border-av-border-thin'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-jriy64i8-fd5f2e9d63bf552d6910d12f255eb26e'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-68e036126b913e5028f77311dc66b825\">\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825 .av-icon-char{\nfont-size:60px;\nline-height:60px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-68e036126b913e5028f77311dc66b825 avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue8c9' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p><strong>Feukam TAKOUNDJOU<\/strong><\/p>\n<p>Soutenance : 09 octobre 2025 \u00e0 14h00<strong><br \/>\n<\/strong>IEMN Amphitheatre - Central Laboratory - Villeneuve d'Ascq<\/p>\n<\/div><\/section>\n<section  class='av_textblock_section av-jtefqx33-26fa44c544b10063385818eda37e027b'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='hr av-kjh3zw-4dff888f744b728a1aca9b3a0971493a hr-default  avia-builder-el-6  avia-builder-el-no-sibling'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<h5><strong><span style=\"color: #800000;\">Jury :<\/span><\/strong><\/h5>\n<ul>\n<li>Daniel Dolfi, Thales Group &#8211; Rapporteur<\/li>\n<li>Giacomo Scalari, ETH Zurich &#8211; Rapporteur<\/li>\n<li>Delphine Marris-Morini, C2N &#8211; Examinatrice<\/li>\n<li>Adel Bousseksou, C2N &#8211; Examinateur<\/li>\n<li>Stefano Barbieri, IEMN &#8211; Directeur de th\u00e8se<\/li>\n<li>Emilien Peytavit, IEMN &#8211; Co-directeur de th\u00e8se<\/li>\n<\/ul>\n<h5><span style=\"color: #800000;\">Summary:<\/span><\/h5>\n<p>Dans cette th\u00e8se, effectu\u00e9e au sein de l\u2019\u00e9quipe Photonique THz du Laboratoire IEMN, j&rsquo;ai \u00e9tudi\u00e9 exp\u00e9rimentalement la r\u00e9alisation un modulateur \u00e9lectro-optique rapide \u00e0 base de GaAs pour la gamme du moyen infrarouge (MIR,3-12 \u03bcm). L&rsquo;objectif est de d\u00e9montrer la faisabilit\u00e9 d&rsquo;un dispositif enti\u00e8rement int\u00e9gr\u00e9, compatible avec les plateformes photoniques MIR en cours de d\u00e9veloppement. Le dispositif vis\u00e9 est un modulateur \u00e0 ondes progressives bas\u00e9 sur un guide d&rsquo;onde MIR monomode int\u00e9gr\u00e9 dans une ligne de transmission microonde. Le guide d&rsquo;onde se base sur un c\u0153ur en GaAs basse temp\u00e9rature (GaAs-BT) et sur des couches de confinement de Al0.52In0.48P. Dans un premier temps, par simulation FDTD, j&rsquo;ai con\u00e7u et optimis\u00e9, dans la gamme 8-10 \u00b5m, deux modulateurs bas\u00e9s sur une ligne microonde microruban et une ligne coplanaire. Ensuite, j&rsquo;ai caract\u00e9ris\u00e9 exp\u00e9rimentalement les guides d&rsquo;onde MIR en mettant en place un banc optique d\u00e9di\u00e9. Je d\u00e9montre qu\u2019en contr\u00f4lant la rugosit\u00e9 des parois lat\u00e9rales du guide, le GaAs-BT permet d&rsquo;atteindre des pertes de propagation inf\u00e9rieures \u00e0 1 dB\/cm. Enfin, en utilisant ces guides d&rsquo;onde, j\u2019ai effectu\u00e9 la premi\u00e8re caract\u00e9risation \u00e0 basse fr\u00e9quence d&rsquo;un modulateur bas\u00e9 sur une ligne microonde coplanaire.<br \/>\n<strong>Mots cl\u00e9s\u00a0:<\/strong> modulateur moyen-infrarouge, effet \u00e9lectro-optique, Guide d\u2019onde GaAs<\/p>\n<h5><span style=\"color: #800000;\">Abstract:<\/span><\/h5>\n<p><strong>Waveguides based on low-temperature grown GaAs : towards an integrated, mid-infrared electro-optic modulator.<\/strong><br \/>\nIn this thesis, that took place in the THz Photonics group at IEMN Laboratory, I studied experimentally the possibility to realize a fast electro-optic modulator based on GaAs and operating in the mid-infrared range (MIR, 3-12 \u00b5m). The objective is to demonstrate the feasibility of a fully integrated device compatible with the MIR photonic platforms that are currently under development. The targeted device is a travelling-wave modulator exploiting a MIR single-mode waveguide integrated in a microwave transmission line. The waveguide is based on a low-temperature grown GaAs (LT-GaAs) core and lattice-matched\u00a0Al0.52In0.48P as low-index cladding. First, through FDTD simulations, I designed and optimized, for the 8-10 \u00b5m range, two modulators based on a microstrip and a coplanar microwave line. Next, I characterized experimentally the MIR waveguides by setting up a dedicated optical bench. With this setup, I show that by controlling the waveguide sidewall roughness, the use of LT-GaAs allows reaching state-of-the art propagation losses below 1 dB\/cm. Finally, using these waveguides, I performed the first low-frequency characterization of a modulator based on a coplanar microwave line.<br \/>\n<strong>Keywords\u00a0:<\/strong> mid-infrared modulator, electro-optic effect, GaAs waveguide<\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":71083,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,8,199],"tags":[],"class_list":["post-75221","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-a-la-une","category-actualites","category-these"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/75221","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=75221"}],"version-history":[{"count":2,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/75221\/revisions"}],"predecessor-version":[{"id":75225,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/75221\/revisions\/75225"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media\/71083"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=75221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=75221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=75221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}