{"id":349953,"date":"2024-02-08T18:02:24","date_gmt":"2024-02-08T18:02:24","guid":{"rendered":"\/forum\/forums\/topic\/diverging-simulation-when-going-from-long-to-short-wavelength\/"},"modified":"2024-02-08T18:02:24","modified_gmt":"2024-02-08T18:02:24","slug":"diverging-simulation-when-going-from-long-to-short-wavelength","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/diverging-simulation-when-going-from-long-to-short-wavelength\/","title":{"rendered":"Diverging simulation when going from long to short wavelength"},"content":{"rendered":"<p>I am having a problem with diverging simulations in Lumerical FDTD. I am trying to simulate am asymmetric directional coupler which runs fine for longer wavelengths (~1600 nm) but when I change the wavelength to ~1000 nm, the simulation diverges.<\/p>\n<p>I have tried the following:- Change to metal boundary conditions<\/p>\n<p>&#8211; Reduce dt stability factor (I have tried reducing this to 0.95, 0.9, 0.5 and 0.1)<\/p>\n<p>Neither of these seem to resolve the issue. Any insight would be greatly appreciated.<\/p>\n","protected":false},"template":"","class_list":["post-349953","topic","type-topic","status-closed","hentry","topic-tag-waveguide-2","topic-tag-divergence-issues","topic-tag-fdtd"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"I am having a problem with diverging simulations in Lumerical FDTD. I am trying to simulate am asymmetric directional coupler which runs fine for longer wavelengths (~1600 nm) but when I change the wavelength to ~1000 nm, the simulation diverges.I have tried the following:- Change to metal boundary conditions- Reduce dt stability factor (I have\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/diverging-simulation-when-going-from-long-to-short-wavelength\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Diverging simulation when going from long to short wavelength | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"I am having a problem with diverging simulations in Lumerical FDTD. I am trying to simulate am asymmetric directional coupler which runs fine for longer wavelengths (~1600 nm) but when I change the wavelength to ~1000 nm, the simulation diverges.I have tried the following:- Change to metal boundary conditions- Reduce dt stability factor (I have\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/diverging-simulation-when-going-from-long-to-short-wavelength\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2024-02-08T18:02:24+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2024-02-08T18:02:24+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Diverging simulation when going from long to short wavelength | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"I am having a problem with diverging simulations in Lumerical FDTD. I am trying to simulate am asymmetric directional coupler which runs fine for longer wavelengths (~1600 nm) but when I change the wavelength to ~1000 nm, the simulation diverges.I have tried the following:- Change to metal boundary conditions- Reduce dt stability factor (I have\" \/>\n\t\t<script type=\"application\/ld+json\" class=\"aioseo-schema\">\n\t\t\t{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/#breadcrumblist\",\"itemListElement\":[{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"position\":2,\"name\":\"Topics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/divergence-issues\\\/#listItem\",\"name\":\"divergence-issues\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/divergence-issues\\\/#listItem\",\"position\":3,\"name\":\"divergence-issues\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/divergence-issues\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/#listItem\",\"name\":\"Diverging simulation when going from long to short wavelength\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/#listItem\",\"position\":4,\"name\":\"Diverging simulation when going from long to short wavelength\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic-tag\\\/divergence-issues\\\/#listItem\",\"name\":\"divergence-issues\"}}]},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/\",\"name\":\"Diverging simulation when going from long to short wavelength | Ansys Learning Forum\",\"description\":\"I am having a problem with diverging simulations in Lumerical FDTD. I am trying to simulate am asymmetric directional coupler which runs fine for longer wavelengths (~1600 nm) but when I change the wavelength to ~1000 nm, the simulation diverges.I have tried the following:- Change to metal boundary conditions- Reduce dt stability factor (I have\",\"inLanguage\":\"en-US\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/diverging-simulation-when-going-from-long-to-short-wavelength\\\/#breadcrumblist\"},\"datePublished\":\"2024-02-08T18:02:24+00:00\",\"dateModified\":\"2024-02-08T18:02:24+00:00\"},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"inLanguage\":\"en-US\",\"publisher\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\"}}]}\n\t\t<\/script>\n\t\t<!-- All in One SEO -->\n\n","aioseo_head_json":{"title":"Diverging simulation when going from long to short wavelength | Ansys Learning Forum","description":"I am having a problem with diverging simulations in Lumerical FDTD. 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