{"id":391935,"date":"2024-10-30T09:23:55","date_gmt":"2024-10-30T09:23:55","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/help-in-bandstructure-simulation\/"},"modified":"2024-10-30T09:23:55","modified_gmt":"2024-10-30T09:23:55","slug":"help-in-bandstructure-simulation","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/help-in-bandstructure-simulation\/","title":{"rendered":"Help in bandstructure simulation"},"content":{"rendered":"<p>&lt;p dir=&#8221;ltr&#8221;&gt;Hi&nbsp;&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;I need help with the bandstructure simulations.. I tried to download two examples and do some changes to suit &ldquo; my structure&rdquo; but I am not getting reasonable results.. I am trying to reproduce a published paper result.&nbsp;&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;&nbsp;Firstly, I tried to solve the problem using the Lumerical &ldquo;mode&rdquo; software. I followed up the following example:&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;<a href=\"https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360042039033-Bandstructure-of-planar-photonic-crystal-with-a-square-lattice-varFDTD\">https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360042039033-Bandstructure-of-planar-photonic-crystal-with-a-square-lattice-varFDTD<\/a>&lt;\/p&gt;&lt;p&gt;<strong>&nbsp;<\/strong>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;My structure is a 1D photonic crystal which consists of a waveguide with one of its side walls looks like a sinusoidal wave.&nbsp;&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;So, after importing the structure, I changed the boundary conditions to be pml&nbsp; in the y-direction, while keeping Bloch boundary condition in the x direction and I give the normalized&nbsp; kx=0.25&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;Based on <a href=\"https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360041566614-Rectangular-Photonic-Crystal-Bandstructure\">https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360041566614-Rectangular-Photonic-Crystal-Bandstructure<\/a>&lt;\/p&gt;&lt;p&gt;<strong>&nbsp;<\/strong>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;k _norm =k_SI * a \/2\/pi&lt;\/p&gt;&lt;p&gt;<strong>&nbsp;<\/strong>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;k_SI=2pi\/lambda, lambda=1550nm&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;a=400nm&lt;\/p&gt;&lt;p&gt;<strong>&nbsp;<\/strong>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;&nbsp;However whenever I run the program it gives me the window that the program is &ldquo;updating slab modes&rdquo; and it&nbsp; stucks.why?&lt;\/p&gt;&lt;p&gt;<strong>&nbsp;<\/strong>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;Second, I tried to solve the problem with FDTD and I followed the following example:&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;<a href=\"https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360042038473-Bandstructure-of-photonic-crystal-waveguide-Line-defect\">https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360042038473-Bandstructure-of-photonic-crystal-waveguide-Line-defect<\/a> with the same changes that I mentioned above&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;&nbsp;And here&rsquo;s what I got when I run the Gamma-X sweep from 0-1&nbsp;&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/lh7-rt.googleusercontent.com\/docsz\/AD_4nXdmgdCTEiJERaOcDmKTC9Lh90UYkBNJQFOFkE5o2E2eN8hfJIK7GlnYpU-fr_KR-b1-oKaFGe2o6GjG-qUeRHKsXqWmh2xKUt7gNG00XkJi3v6-3zB5GZ6gz9AyoJMceCLdx3V30cI21X2m5vNxwpIw_3-D?key=0M7_qdCxO3pVLdsQ_myuWQ\" width=\"624\" height=\"223\" \/>&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;I tried to do many changes in the apodization width and center, to change the kx , changing frequencies ..etc. But all my trials doen&#8217;t help.&lt;\/p&gt;&lt;p dir=&#8221;ltr&#8221;&gt;So what are the possible changes that I can do to obtain a clear bandstrure?&nbsp;&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-391935","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["3631","2592"],"_bbp_author_ip":["132.64.56.226"],"_btv_view_count":["94"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["391935"],"_bbp_forum_id":["27796"],"_bbp_engagement":["2592","3631"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["392322"],"_bbp_last_active_id":["392322"],"_bbp_last_active_time":["2024-10-31 20:52:17"]},"test":"jinan-nijemmail-huji-ac-il"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/391935","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\/391935\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=391935"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}