What does XSim simulate?

Electromagnetic and photonic devices in one, two or three dimensions: photonic integrated circuit components such as waveguides, microring resonators and couplers, and RF structures such as antennas, arrays, metal waveguides and cavities. It also handles scattering and far-field problems, including radar cross-section.

Which solver does XSim use?

Finite-difference time-domain, run by Tech-X’s Vorpal engine — the same engine behind VSim. Conformal meshing handles curved conductors and dispersive dielectrics, a mode solver launches real guided modes, and because it is a time-domain method one broadband run returns the response across a whole wavelength range.

Can XSim import a GDS layout?

Yes. XSim imports GDS, STEP and STL. A GDS layout is extruded into a 3D structure, and roughness can be added to it to model manufactured sidewalls rather than drawn ones. Geometry can also be built directly in XSimComposer’s 3D geometry builder.

Does XSim run on GPUs or in the cloud?

Both. GPU runs need a CUDA-capable NVIDIA card with a driver supporting CUDA 12.3, and the problem must fit in the card’s memory; work can be spread across several GPUs. In the cloud, Tech-X’s CloudCompute runs XSim on your own AWS account rather than on a hosted service.

What is the difference between XSim and TCAD optical simulation?

Different jobs. Victory Device’s Luminous module puts optics inside a device simulation — light absorbed in a photodiode or image sensor and turned into carriers. XSim is a standalone full-wave solver for how light propagates through a component and what comes out. How Silvaco intends the two to relate is not published.

Is there an evaluation?

Yes. Tech-X offers a free 30-day XSim evaluation, requested through txcorp.com, where support and licensing also still sit. XSim is licensed per compute platform, which Tech-X defines as either a single workstation or a whole cluster, so say which you intend to evaluate on.

XSim Photonics: electromagnetic and photonic device simulation

See how light and RF energy move through your waveguides, resonators, couplers and antennas, and test each design choice before it reaches a mask.

Talk to our Technical Experts Downloads and documentation

What XSim Photonics does

XSim Photonics is an electromagnetic solver for photonic and RF devices. It handles waveguides and other photonic integrated circuit components through to antenna arrays, on x86 CPUs or NVIDIA GPUs. You bring the geometry and the materials. You get back S-parameters and far-field results, the numbers that decide whether a component goes to tape-out as drawn.

Capabilities

Computational

Constant or variable gridding, driven by broadband or monochromatic sources. Conformal conductors, dispersive dielectrics and resistive materials, so a curved or lossy structure is modeled as drawn. Phase-shifted periodic boundaries, adiabatic absorbers, launch and exit ports, and a total-field / scattered-field source cover periodic, open and port-driven problems.
Workflow and setup

One interface takes you from setup to visualization, and you can script every step. Import GDS, STEP or STL geometry, or build it in the Composer 3D geometry builder. Pick materials from the library or define your own. A mode solver sets up the guided modes you launch, and monitors go wherever you need the data.
Computing platforms

Runs on x86 CPUs and NVIDIA GPUs, and distributes the computing across either when one machine isn't enough. Windows, Linux or Mac, from a laptop to a supercomputer, or on AWS using the Tech-X CloudCompute service.
Analysis and output

S-parameters against wavelength, the form a circuit-level simulation needs for a passive photonic component, and far-field transformations for anything that radiates. Inside the structure, 3D visualization with slicing and contours, Fourier transformation and regional energy analysis show you where the energy goes.

Works with

Takes in

a GDS layout, a STEP or STL model, or geometry built in Composer, plus the materials you assign to it.

Produces

S-parameters and far-field results you can analyze per component, or drop into a circuit-level simulation as blocks.

Explore photonic simulation at Silvaco

What you can simulate

Where XSim Photonics already runs

XSim came to Silvaco with Tech-X in 2025, along with Tech-X's work on multi-node GPU simulation for photonics.

Send us the component that didn't measure the way it simulated

Talk to our Technical Experts Downloads and documentation

XSim Photonics questions

Photonic and RF devices. For photonics, that means integrated circuit components such as waveguides, resonators, couplers and modulators. For RF, it means antennas, antenna arrays and other RF components. XSim Photonics also handles general component-level electromagnetic problems, and returns S-parameters and far-field results for all of them.

Conformal conductors and dispersive dielectrics represent curved and lossy structures as drawn, and a mode solver sets up the guided modes you launch. Broadband or monochromatic sources let you cover a whole wavelength range or check a single wavelength.

Yes. XSim imports GDS layouts as well as STEP and STL models, so the geometry you've already drawn is the geometry you simulate. No file yet? Build the structure in the Composer 3D geometry builder. Either way, it goes through the same setup, materials and monitors.

Both. XSim runs on x86 CPUs and NVIDIA GPUs, and can distribute a run across either, on anything between a laptop and a supercomputer. For cloud runs, the Tech-X CloudCompute service puts XSim on AWS. The documentation lists the GPU and memory a given problem size needs.

Different questions. Silvaco's TCAD optoelectronics tools model light inside the device: image sensors, solar cells, lasers and optical sensors. They follow what the light does to the device's electrical behavior. XSim works on the light itself: how it travels through a component and what comes out the other end.

Yes. Talk to our Technical Experts with the component, layer stack and wavelength range you want to test, and the workstation or cluster you'd run it on. They'll scope the evaluation with you. University research groups apply through the University Program instead; more than 200 universities already run Silvaco tools that way.