The official hub for Lumerical support is the Ansys Learning Forum (ALF), which replaced the old Lumerical Knowledge Exchange (KX). This forum is the primary place to troubleshoot simulations, discuss photonics design, and interact with Ansys application engineers. Getting Started on the Forum
Account Setup: You must create a dedicated Ansys Learning Forum account to post questions or replies; old KX credentials are not automatically linked.
Primary Category: Most Lumerical discussions are found under the Photonics Category, which includes sub-tags for specific tools like FDTD, MODE, and CHARGE.
Browsing Content: Use the Lumerical Forum search to filter by "Answered Questions" or sort by "Recent Activity" to find existing solutions before posting. Effective Posting Guidelines
No File Attachments: A critical rule of the ALF is that Ansys employees are not permitted to download user attachments.
Use Screenshots: Instead of project files, provide clear screenshots of your simulation settings, geometry, and error messages to get feedback.
Be Specific: When posting a new thread, include the specific Lumerical product version you are using and clearly describe the expected vs. actual results. Key Resources and Tags
Application Gallery: For pre-built examples, check the Lumerical Application Gallery, which is often linked within forum discussions.
Innovation Courses: Many forum answers point to free Ansys Innovation Courses for deeper technical background on simulation theories.
Common Tags: Discussions are frequently organized by tags such as Creating Monitors, Material Database, and Interoperability.
The forum is part of the Ansys Customer Center and is designed to provide public community support, troubleshooting, and collaborative learning for researchers and engineers.
Official Platform: Access the Lumerical Forum directly on the Ansys Innovation Space.
Community Transition: In 2021, Lumerical's independent community support fully merged into the broader Ansys Learning Forum (ALF) to streamline resource access. Core Discussion Categories
Discussion is typically organized by product and physics solver to help users find relevant expert advice: FDTD: Designing and optimizing complex photonic components. MODE: Optical waveguide design and analysis.
CHARGE / HEAT / FEEM: Multiphysics simulations involving electrical, thermal, and mechanical interactions.
INTERCONNECT: Photonic integrated circuit (PIC) and system-level modeling.
Scripting & API: Automating tasks using Lumerical's scripting language or Python (PyLumerical). Recent Trending Topics (April 2026)
Recent activity on the Ansys Learning Forum highlights current user priorities and technical issues: Lumerical Forum - Ansys Customer Center The Ansys Learning Forum is a public forum. Ansys Innovation Space ANSYS LUMERICAL - Ansys Customer Center
The Virtual Cleanroom: The Role and Impact of the Lumerical Forum
In the highly specialized and technically demanding field of photonics, simulation software acts as the bridge between theoretical design and physical realization. Among the suite of tools available, Ansys Lumerical stands as an industry standard for photonic component design. However, behind the complex algorithms of FDTD (Finite-Difference Time-Domain) and MODE solvers lies an equally critical infrastructure: the Lumerical Forum. More than a simple bulletin board for bug reports, the Lumerical Forum functions as a decentralized university, a technical support repository, and the central nervous system for a global community of optical engineers.
The primary value of the Lumerical Forum lies in its role as a repository of institutional knowledge. Photonic simulation is rarely a straightforward process of "plug-and-play." It involves navigating a labyrinth of mesh refinement, boundary conditions, material dispersion, and convergence testing. When an engineer encounters a "diverging simulation" error or unexpected results in a far-field projection, the forum serves as the first line of defense. Unlike a static textbook, the forum is a dynamic, searchable database of solved problems. A doctoral student struggling with a specific 2D material model may find a thread from five years prior where a senior application engineer explained the nuances of surface conductivity boundaries. In this sense, the forum lowers the barrier to entry, allowing newcomers to stand on the shoulders of those who have debugged the path before them.
Furthermore, the forum facilitates the "peer review" of simulation methodologies. In experimental physics, results are validated through replication in other labs; in computational photonics, validation comes from proving that a simulation is physically accurate and numerically stable. The forum provides a platform for this scrutiny. Users frequently post their simulation files or scripts, inviting critique on their mesh settings or source injection axes. This collaborative troubleshooting is vital because it forces engineers to articulate their assumptions. When a user explains why they chose a specific simulation span or time step, they are engaging in a pedagogical process that reinforces the community’s collective understanding of the underlying physics.
The forum is also an indispensable resource for bridging the gap between simulation and fabrication. While Lumerical provides the solvers, the application of these tools to real-world foundry processes—such as silicon photonics or InP platforms—often requires custom scripts and workflows. The forum hosts a wealth of user-generated content, including scripting examples for automation, Python API integrations, and CML (Compact Model Library) generation techniques. This exchange of code accelerates the design cycle, moving the industry forward by preventing engineers from "reinventing the wheel" for routine tasks like
Based on the typical style and content found on the Ansys Lumerical Forum, here are a few examples of what a "post" usually looks like.
I have provided three common archetypes: a New Discussion (Question), a Reply/Solution, and an Example Script/Code Share.
| Symptom | Likely fix |
|---------|-------------|
| FDTD diverging | Increase mesh, reduce time step, check material fitler |
| CHARGE not converging | Increase iteration limit, refine mesh at junction, check BCs |
| Monitor data looks NaN | Run with smooth mesh off, check geometry overlap |
| INTERCONNECT error | Check element names for spaces, rebuild netlists |
| Script error “unexpected symbol” | Verify Lua syntax – use ? command in script prompt |
Use this guide to become effective on the Lumerical forum. When in doubt, search first, then post a minimal working example. The community and Ansys engineers are active, but good questions get answered within 24–48 hours.
The "story" of the Lumerical forum is defined by a major transition from a small, dedicated community to its integration into a global corporate ecosystem following Ansys's acquisition of Lumerical in early 2020 [34]. The "KX" Legacy and the Big Move For years, the Lumerical Knowledge Exchange (KX)
was the heartbeat of the photonics community. It was a specialized hub where researchers and engineers shared highly technical simulation tips and custom scripts. The Disruption:
In June 2021, Ansys moved the community support from the original KX platform to the Ansys Learning Forum (ALF) The Struggle:
The transition was controversial; users initially complained that over 10,000 legacy topics
could not be fully migrated, leading to a temporary loss of searchable knowledge that "compromised" ongoing work for some researchers [5]. The Forum Today: A Multi-Layered Hub The modern Lumerical Forum is now part of the Ansys Innovation Space
. It serves as a troubleshooting center where users solve highly specific problems: Simulation & Scripting: Users frequently exchange custom scripts
to automate complex tasks like sweeping waveguide thickness or calculating single-mode propagation Version Transitions:
A recurring "story" in the threads involves users troubleshooting discrepancies when moving to newer versions (like ), which introduced a modern tabbed user interface and enhanced GPU support [4, 12]. Interoperability:
Much of the modern discussion focuses on how Lumerical integrates with other tools, such as Python APIs
, and other Ansys products like HFSS for electrode modeling [7, 9, 18]. Key Forum Resources Technical Support: Ansys Innovation Space is the current active home for the forum [1]. Knowledge Base: Ansys Optics Center
The Lumerical Forum, previously known as the Knowledge Exchange (KX), is the primary hub for photonics researchers and engineers seeking technical support for Lumerical's simulation tools. Since April 2021, the community has migrated to the Ansys Learning Forum (ALF) following Ansys's acquisition of Lumerical. Key Platform Transition
New Home: All Lumerical community support now resides within the Photonics category of the Ansys Learning Forum. lumerical forum
Unified Access: Users must create an ALF account to post, though a Lumerical support registration is no longer strictly required for basic access.
Expert Involvement: Lumerical Application Engineers actively monitor the forum to provide professional guidance alongside community experts. Critical Posting Guidelines
No File Attachments: Due to security policies, Ansys employees cannot download attachments.
Use Screenshots: To get feedback on project settings or error messages, you should provide clear screenshots instead of simulation files.
Tags and Categories: Use tags like FDTD, MODE, or CHARGE to ensure your query reaches the right sub-specialists. Resources Available
Application Gallery: Provides pre-built simulation examples for gratings, waveguides, and metasurfaces.
Innovation Courses: Offers free, self-paced learning modules for beginners and advanced users.
Knowledge Base: A library of technical documentation and "Watch & Learn" videos for specific simulation workflows.
💡 Pro Tip: Before posting a new question, use the search filter to check for "Answered Questions." Most common scripting errors and convergence issues have already been addressed in detail by the community.
If you are looking for something specific, I can help you find:
Simulation examples for a specific device (e.g., Bragg gratings, solar cells)
Scripting commands for the Lumerical Script File (.lsf) environment
Installation guides for high-performance computing (HPC) setups
The "Lumerical Forum," officially part of the Ansys Learning Forum (ALF)
, is the primary community support hub for users of Ansys Lumerical photonics simulation software. It serves as a technical exchange for engineers and researchers working on nanophotonic devices, circuits, and systems. Ansys Innovation Space Core Purpose and Community Role Technical Support:
Users post queries regarding simulation errors, script usage, and product licensing. Knowledge Exchange:
It replaced the former "Lumerical Knowledge Exchange (KX)" in April 2021 to integrate Lumerical support into the broader Ansys ecosystem. Expert Interaction:
Support is provided by both Ansys Application Engineers and high-contributing community members. Ansys Innovation Space Key Discussion Topics
The forum is organized into categories and tags to help users navigate complex multiphysics workflows:
Deep dives into FDTD (Finite-Difference Time-Domain), MODE, RCWA (Rigorous Coupled-Wave Analysis), and CHARGE solvers. Design Optimization: Discussions on inverse-design and topology optimization. Automation:
Guidance on using the Lumerical Python API and custom scripting for automated design processes. Interoperability:
Workflows connecting Lumerical with other Ansys tools like Zemax OpticStudio, Speos, and HFSS. Ansys Innovation Space Forum Features Searchable Knowledge Base:
A vast archive of "Answered Questions" that acts as a crowdsourced manual for troubleshooting. Ansys Innovation Space: Integrated with Ansys Innovation Courses to provide structured learning alongside community advice. Public Access:
While some advanced support requires a subscription, the forum remains a public resource for the global photonics community. Ansys Innovation Space Primary Solvers Covered Lumerical Forum - Ansys Customer Center The Ansys Learning Forum is a public forum. Ansys Innovation Space Photonics - Ansys Customer Center
Unlocking the Power of Numerical Analysis: A Comprehensive Guide to Lumerical Forums
In the realm of numerical analysis, computational physics, and engineering, Lumerical Forums have emerged as a vital platform for researchers, scientists, and engineers to share knowledge, discuss ideas, and collaborate on solving complex problems. Lumerical, a renowned company in the field of photonics and electromagnetics, has created a comprehensive online forum that serves as a hub for users to exchange information, showcase their work, and get help from experts.
What is Lumerical?
Lumerical is a leading provider of software solutions for designing, simulating, and optimizing photonic and electromagnetic systems. Their flagship product, FDTD Solutions, is a powerful tool for modeling and analyzing the behavior of light in various structures, materials, and systems. Lumerical's software is widely used in industries such as photonics, optics, and electrical engineering, and has applications in fields like telecommunications, data centers, and biomedical research.
The Lumerical Forum: A Community-Driven Platform
The Lumerical Forum is an online platform where users can ask questions, share their experiences, and learn from others who have faced similar challenges. The forum is divided into various sections, each focused on specific topics, such as:
Benefits of Engaging with the Lumerical Forum
The Lumerical Forum offers numerous benefits to its users, including:
How to Make the Most of the Lumerical Forum
To maximize the benefits of the Lumerical Forum, users can follow these best practices:
Conclusion
The Lumerical Forum is a powerful resource for researchers, scientists, and engineers working in the fields of photonics, electromagnetics, and numerical analysis. By engaging with the forum, users can tap into a collective knowledge base, get help from experts, and stay up-to-date with the latest developments in Lumerical software. Whether you're a seasoned user or new to Lumerical software, the forum offers a wealth of information, resources, and community support to help you achieve your goals. So, join the conversation, ask questions, share your experiences, and unlock the full potential of Lumerical software!
I can't directly access or pull a specific post from the Lumerical forum (now part of the Ansys Learning Forum), since it requires live login and search. However, I can give you an example of what a typical help post looks like there, along with common responses.
Example post title:
"FDTD: Unexpected transmission dip for simple grating structure" The official hub for Lumerical support is the
Post content:
User:
I'm simulating a 1D grating (period 500 nm, duty cycle 0.5, thickness 100 nm, Si on SiO₂). Plane wave source at normal incidence, wavelength range 400–800 nm. Transmission monitor placed after the structure.I see a sharp dip at ~650 nm that I don't expect from theory (should be a smooth response). Mesh refinement is set to 'conformal variant 1', and I've tried both 'staircase' and 'conformal' meshing.
I also checked convergence by reducing mesh step to 5 nm – dip remains but shifts slightly.
Any idea what's causing this? Could it be a resonance artifact or boundary reflection? PML layers are 8 layers with 'standard' profile.
Typical reply from forum expert:
Moderator/User:
That sounds like a guided-mode resonance or possibly a numerical artifact. A few things to check:
- Try 'steep angle' PML profile or increase PML layers to 12.
- Ensure your simulation time is long enough – add an autoshutoff min of 1e-6 and check the time signal.
- Run a test with a single frequency point at 650 nm and use a broadband field monitor to see field profile at that wavelength.
- If using periodic boundaries, confirm the Bloch vector is set to 0 (normal incidence).
- Try switching to 'mesh order' = 'volume average' in material properties.
Post a screenshot of your layout and the transmission spectrum if possible.
If you want to find a real specific post, you can search the Ansys Learning Forum > Lumerical using keywords like:
Would you like help formulating a new post to ask a specific Lumerical question?
Mastering the Lumerical Forum: Your Ultimate Resource for Photonic Simulation
In the rapidly evolving world of nanophotonics and optoelectronics, having the right tools is only half the battle. The other half is knowing how to use them to solve complex, real-world problems. For users of Ansys Lumerical, the Lumerical Forum (now part of the Ansys Innovation Space) is the beating heart of this learning process.
Whether you are a PhD student troubleshooting a grating coupler design or an industry engineer optimizing a CMOS image sensor, the Lumerical Forum is an indispensable asset. Here is how to navigate and leverage this community to accelerate your research. What is the Lumerical Forum?
The Lumerical Forum is a global community platform where researchers, engineers, and students gather to discuss simulation methodologies, troubleshoot script errors, and share insights into photonics design.
Since Lumerical’s acquisition by Ansys, the forum has been integrated into the Ansys Innovation Space. It serves as a living library of collective knowledge, covering the entire Lumerical suite, including: FDTD: 3D electromagnetic field solver. MODE: Waveguide design and analysis. CHARGE, HEAT, and DGTD: Multiphysics solvers. INTERCONNECT: Photonic integrated circuit (PIC) simulator. Why Use the Forum? 1. Expert Troubleshooting
Photonic simulations are notorious for being computationally expensive and sensitive to boundary conditions. On the forum, you can find solutions to common "Simulation Diverged" errors or advice on setting up perfectly matched layers (PML) to avoid unphysical reflections. 2. Scripting Support
Lumerical’s scripting language (LSF) and its Python API are powerful but have a learning curve. The forum is filled with code snippets for automating sweeps, extracting S-parameters, and post-processing complex data sets. 3. Direct Access to Support Engineers
While the community is peer-driven, Ansys application engineers frequently chime in. This ensures that the advice provided aligns with the latest software updates and best practices. 4. Application-Specific Galleries
The forum often links to or hosts discussions on the Application Gallery. If you are working on a specific technology—like edge couplers, micro-ring resonators, or metalenses—there is likely already a forum thread discussing the nuances of that specific model. Tips for Getting the Most Out of the Community
To get high-quality answers quickly, follow these forum best practices:
Search First: With over a decade of archived discussions, there is a 90% symbol chance your question has been answered. Use keywords like "PML reflection," "Mode expansion," or specific error codes.
Provide a Minimal Working Example (MWE): Instead of describing a complex project, upload a simplified version of your .fsp or .lms file. This allows others to run the simulation and find the exact bottleneck.
State Your Version: Lumerical updates frequently. Always mention if you are using an older version or the latest Ansys Lumerical release, as certain features or script commands may have changed.
Use Visuals: A screenshot of your monitor geometry or a plot of the "incorrect" results helps experts diagnose issues at a glance. Beyond Troubleshooting: A Learning Hub
The Lumerical Forum isn't just for when things go wrong; it’s a place to stay ahead of the curve. You can discover: Feature Requests: See what’s coming in future releases.
Webinar Links: Stay updated on deep-dive sessions hosted by Ansys experts.
Methodology Debates: Engage in higher-level discussions about when to use FDTD versus EME (Eigenmode Expansion) for specific device architectures. Conclusion
The Lumerical Forum is more than just a support desk; it is a collaborative ecosystem that lowers the barrier to entry for complex photonic design. By participating in the forum, you aren't just solving a simulation error—you are contributing to a global knowledge base that pushes the boundaries of what’s possible with light.
Are you currently stuck on a specific simulation error or looking for a scripting template to automate your workflow?
The most active section. Topics range from mesh refinement strategies to multi-coefficient material models. Common threads include optimizing simulations for metal optics (e.g., silver/gold at visible wavelengths) and reducing simulation time for large-scale solar cells.
This is a post sharing a script to automate a parameter sweep.
Subject: [Script] Automating parameter sweeps for varying waveguide widths
Body: Hello community,
I wrote a simple script to automate the process of sweeping waveguide widths and exporting the effective index data to a text file. I thought this might be useful for others doing similar MODE calculations.
How to use:
Code:
# Define sweep parameters
width_start = 0.4e-6;
width_stop = 1.0e-6;
steps = 10;
# Open file for writing
filename = "neff_vs_width.txt";
f = fopen(filename, "w");
# Loop
for (i=0:steps-1)
current_width = width_start + i*(width_stop-width_start)/(steps-1);
# Update structure (assuming object named 'waveguide')
setnamed("waveguide", "x span", current_width);
# Run mode calculation
run;
# Get data
neff = getdata("mode1", "neff");
# Write to file
fprintf(f, "%e %e\n", current_width, neff);
fclose(f);
?"Sweep complete. Data saved to " + filename;
Hope this helps!
Are you looking for help with a specific Lumerical problem, or were you trying to format a post to submit? The Virtual Cleanroom: The Role and Impact of
The Ansys Lumerical Forum (formerly the Lumerical Knowledge Base and Community) is the primary hub for users of Lumerical’s photonics simulation tools to find support, share expertise, and troubleshoot technical issues. Platform Overview
The forum is hosted within the Ansys Innovation Space, a unified platform for Ansys users. It is categorized alongside other optical simulation tools like Zemax and Speos to facilitate cross-platform workflows and interoperability. Key Features & Usage
Discussion Topics: Users can post technical questions regarding simulation setup, script debugging (Lumerical Script Language), and specific application areas like CMOS image sensors, waveguides, or metalenses.
Expert Support: Ansys engineers and experienced community members ("Lumerical experts") frequently provide verified answers to complex modeling questions. Reporting Mechanisms:
Topic Reporting: Logged-in users can report specific topics or posts that may be off-topic or violate community guidelines.
Data Reporting: For simulation results, Ansys tools typically use a "Quick Report" or "Create Report" feature to generate rectangular plots and S-parameter data directly from the software interface.
Searchability: The forum uses Topic Tags (e.g., "physics coupling interface," "eye diagrams," "geometry reader") to help users navigate archived solutions without starting new threads. Engagement Best Practices To get the most out of the Lumerical community:
Search First: Most common simulation errors or scripting questions have already been addressed in existing threads.
Provide Context: Successful posts typically include the software version, specific error messages, and, if possible, a simplified version of the .fsp or .lms simulation file.
Use the App Gallery: For standard designs, the Ansys Application Gallery provides pre-built templates that often resolve basic setup questions found on the forum. Lumerical Forum - Ansys Customer Center
Please Login to Report Topic. × Please Login to Share Feed. × Anuja Burambadkar. Cancel Save Reply as Draft Publish. Ansys Innovation Space Writing Forum Posts and Responses
Title: Optimizing FDTD Simulation of a Photonic Crystal Structure
Description:
Hi everyone,
I'm working on simulating a photonic crystal structure using Lumerical's FDTD solver. I've been trying to optimize the simulation to achieve accurate results within a reasonable computation time. I'd love to hear from others who have experience with similar simulations.
My structure consists of a 2D array of air holes in a silicon background, with a lattice constant of 500 nm. I'm using a Gaussian source with a wavelength range of 1500-1600 nm. I've meshed the structure with a maximum mesh size of 20 nm.
To optimize the simulation, I've tried the following:
However, I'm still experiencing some issues with accuracy and computation time. Has anyone else encountered similar challenges? What strategies have you used to optimize your FDTD simulations?
Specifically, I'd like to know:
Any advice or insights would be greatly appreciated. I've attached my simulation file (.lms) for reference.
Attachments: photonic_crystal.lms
Tags: FDTD, photonic crystal, optimization
This post is well-written because it:
Ansys Lumerical Learning Forum is the primary hub for users to discuss simulation setups and troubleshoot discrepancies between their results and those found in "proper papers" (published research). Understanding "Proper Paper" Discrepancies
A common topic on the forum is why a user's simulation doesn't match a published paper. Experts typically point to several critical factors: Ansys Innovation Space Unique Software Features
: Lumerical has specific settings and algorithms that new users must learn before achieving reliable, paper-quality results. Published "Best" Results
: Research papers often present the most optimized results from hundreds of different simulation configurations. Sensitivity to Accuracy : Minor differences in mesh accuracy PML (Perfectly Matched Layer) thickness, or simulation time
can lead to significant deviations in sensitive measurements like phase shift or power. Ansys Innovation Space Key Forum Resources for Paper Reproduction Lumerical Learning Forum (Photonics)
: The main sub-forum for Q&A on FDTD, MODE, CHARGE, and other solvers. Ansys Insight: Result Discrepancies
: A dedicated article explaining why your simulation might differ from a peer-reviewed paper or experiment. Convergence Testing Guide
: Crucial documentation for ensuring your simulation has converged to a stable, accurate result suitable for publication. Ansys Innovation Space Specific Simulation Fixes
If you are struggling to match a paper's results, forum experts often recommend: Mesh Refinement
: Reducing "max edge length" or increasing "max refine steps" for complex structures. Material Modeling : Checking the multi-coefficient model fit
for dispersive materials to ensure the simulation accurately represents the real-world material. Source Configuration
: Ensuring correct usage of plane waves, dipoles, or integrated mode sources based on the paper's experimental setup. Ansys Optics Are you trying to reproduce a specific figure from a paper, and if so, what is the material or structure you are simulating?
In the high-stakes world of nanophotonics, semiconductor design, and metamaterials, simulation accuracy is everything. Engineers and researchers using Ansys Lumerical—whether for FDTD, MODE, or the INTERCONNECT suite—often find themselves at a crossroads. The software is powerful, but the physics is complex.
This is where the Lumerical Forum becomes an indispensable asset. Far more than a standard Q&A board, the official Lumerical community is a dynamic ecosystem of peer-to-peer support, expert verification, and script-sharing. Whether you are debugging a divergent simulation or optimizing a grating coupler, mastery of the Lumerical Forum can cut your development time in half.
While the Lumerical Forum is the best official source, you should also leverage:
While Stack Overflow is useful for general programming, the Lumerical Forum often features direct responses from the engineers who wrote the solver code. When a user identifies a potential bug or an undocumented feature, an Ansys moderator will escalate it internally. This feedback loop is invaluable for academic publishing and industrial tape-outs.
The community frequently shares custom analysis groups, script functions, and material databases. For instance, a user might upload an advanced eigenvalue solver for ring resonators or a custom mesh override setting for plasmonic structures. These resources are pre-vetted by the community, saving you weeks of reinventing the wheel.
[code] ... [/code] or use triple backticks ```lua.