{"id":249289,"date":"2023-02-09T18:13:33","date_gmt":"2023-02-09T18:13:33","guid":{"rendered":"\/forum\/forums\/topic\/nonlinear-material-analysis\/"},"modified":"2023-02-10T14:51:04","modified_gmt":"2023-02-10T14:51:04","slug":"nonlinear-material-analysis","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/nonlinear-material-analysis\/","title":{"rendered":"Nonlinear material analysis"},"content":{"rendered":"<p>Hi, thanks in advance for your attention.<br \/>I am using FDTD 3D in Lumerical to model and analyze a Multi-Mode Interferometer coupler whose material to implement is Silicon-rich Silicon Nitride with a linear refractive index of 2.49 and a nonlinear refractive index of 1.61e-18 m^2\/W at 1550 nm operating wavelength. When I insert in Material Database a material with only the linear refractive index of 2.49 I can obtain an effective source mode to launch as follows:<br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966021-ab.png\" alt=\"\"><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966033-ac.png\" alt=\"\"><br \/>If I insert the nonlinear refractive index through inserting the linear (obtained by the square of linear refractive index minus 1)&nbsp; and third order susceptibilities (for example this value known) by using this new material:<br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966100-ad.png\" alt=\"\"><br \/>I obtain very different effective index value with the same geometry and same in linear regime:<br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966260-ae.png\" alt=\"\"><br \/>Also by using a base material, it improves but not the same value:<br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966301-af.png\" alt=\"\"><br \/><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/02\/09-02-2023-1675966316-ag.png\" alt=\"\"><br \/>I would ask you how to make a convergence between the results but at the same time defining the linear and nonlinear refractive index of my material.<\/p>\n<p>Thanks!<\/p>\n","protected":false},"template":"","class_list":["post-249289","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["274734","33648"],"_bbp_author_ip":["23.56.168.214"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1104"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["249289"],"_bbp_forum_id":["27833"],"_bbp_engagement":["33648","274734"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["249446"],"_bbp_last_active_id":["249446"],"_bbp_last_active_time":["2023-02-10 18:29:04"]},"test":"chinna-devarapumtu-ie"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/249289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/249289\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=249289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}