{"id":394707,"date":"2024-11-21T10:18:37","date_gmt":"2024-11-21T10:18:37","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-get-rid-of-slab-modes-in-eme-solver\/"},"modified":"2024-11-21T10:18:37","modified_gmt":"2024-11-21T10:18:37","slug":"how-to-get-rid-of-slab-modes-in-eme-solver","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-get-rid-of-slab-modes-in-eme-solver\/","title":{"rendered":"How to get rid of slab modes in EME solver"},"content":{"rendered":"<p>&lt;p&gt;When simulating adiabatic coupling between SOI taper and polymer, considering the following structure:&lt;\/p&gt;&lt;p&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/11\/21-11-2024-1732183685-mceclip1.png\" width=\"459\" height=\"276\" \/>&lt;\/p&gt;&lt;p&gt;The EME solver finds, of course, slab modes. The fundamental mode of the waveguide, which is the taper, in the middle, can be only found as the 15th mode. Even if I select this 15th mode, which is the one I am interested, when doing the propagation sweep, the adiabatictly coupling is near to zero. No light couples to the polymer.&nbsp;&lt;\/p&gt;&lt;p&gt;When then I remove the Si slab, and simulate the strucuture:&lt;\/p&gt;&lt;p&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/11\/21-11-2024-1732183747-mceclip2.png\" width=\"479\" height=\"293\" \/>&lt;\/p&gt;&lt;p&gt;Then I get this nice result:&lt;\/p&gt;&lt;p&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/11\/21-11-2024-1732183876-mceclip3.png\" width=\"432\" height=\"324\" \/>&lt;\/p&gt;&lt;p&gt;Of course, the mode 1 in the previous strucuture is the fundamental mode of the taper waveguide, and the other modes are cladding modes and etc.&nbsp;&lt;\/p&gt;&lt;div&gt;I don&#8217;t understand why I can&#8217;t achieve any coupling in the first structure, even when I select the desired mode that, in reality, will be the mode we intend to excite in the waveguide. Is it because this mode is the 15th one and not the Mode 1?&nbsp;&lt;\/div&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;div&gt;Would be nice to have some help on that.&lt;\/div&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;div&gt;Thank you.&lt;\/div&gt;&lt;div&gt;&nbsp;&lt;\/div&gt;&lt;div&gt;Taynara&lt;\/div&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-394707","topic","type-topic","status-publish","hentry","topic-tag-waveguide-2","topic-tag-coupling","topic-tag-lumerical","topic-tag-taper","topic-tag-wrong-modes-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["432669","18532"],"_bbp_author_ip":["139.63.203.138"],"_btv_view_count":["266"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["394707"],"_bbp_forum_id":["27833"],"_bbp_engagement":["18532","432669"],"_bbp_voice_count":["2"],"_bbp_reply_count":["5"],"_bbp_last_reply_id":["395745"],"_bbp_last_active_id":["395745"],"_bbp_last_active_time":["2024-11-29 11:25:24"]},"test":"taynara-deoliveiratno-nl"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/394707","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\/394707\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=394707"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}