{"id":346922,"date":"2024-01-29T04:36:00","date_gmt":"2024-01-29T04:36:00","guid":{"rendered":"\/forum\/forums\/topic\/how-to-set-the-group-index-in-this-example-bragg-grating-initial-design\/"},"modified":"2024-01-29T04:36:00","modified_gmt":"2024-01-29T04:36:00","slug":"how-to-set-the-group-index-in-this-example-bragg-grating-initial-design","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-set-the-group-index-in-this-example-bragg-grating-initial-design\/","title":{"rendered":"how to set the group index in this example, &#8216;Bragg grating initial design&#8217;?"},"content":{"rendered":"<div>Hello, everyone.<\/div>\n<div>&nbsp;<\/div>\n<div>I&#8217;m trying to follow the example, so-called bragg grating initial design(https:\/\/optics.ansys.com\/hc\/en-us\/articles\/360042304394-Bragg-grating-initial-design-with-FDTD), and would like to change some structure parameters.<\/div>\n<div>&nbsp;<\/div>\n<div>In this example, the group index is set in the model script.<\/div>\n<div>I thought that it meant the group index of the center wavelength for the Si waveguide with averaged width. When I compared two data, 4.3874 and my calculation value from the MODE group index calculation, there is a bit gap.<\/div>\n<div><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/01\/29-01-2024-1706502652-mceclip1.png\" width=\"655\" height=\"374\"><\/p>\n<\/div>\n<div>Therefore, I would be grateful if anyone could explain the conditions of the group index in the example. I cannot be certain that it is a group index with the averaged Si waveguide.<\/div>\n<div>&nbsp;<\/div>\n<div>Thank you.<\/div>\n","protected":false},"template":"","class_list":["post-346922","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["276558","2796"],"_bbp_author_ip":["23.206.193.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["496"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["346922"],"_bbp_forum_id":["27833"],"_bbp_engagement":["2796","276558"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["347287"],"_bbp_last_active_id":["347287"],"_bbp_last_active_time":["2024-01-30 13:12:23"]},"test":"ddol410hanyang-ac-kr"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/346922","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\/346922\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=346922"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}