Tutorial | Lumerical Fdtd

Calculate how well a fiber mode couples to your chip. Use the couple function in the script:

Start with the Ansys blog on FDTD basics to understand the "resonance region" discretization.

neff = getneff("monitor"); ?"Effective Index: " + num2str(neff); lumerical fdtd tutorial

# Clean the current environment workspace newproject; save("soi_waveguide_automated.fsp"); # Add the Oxide Substrate addblock; set("name", "Substrate_SiO2"); set("material", "SiO2 (Glass) - Palik"); set("x span", 6e-6); set("y span", 4e-6); set("z min", -1e-6); set("z max", 0); # Add the Silicon Waveguide Core addblock; set("name", "Si_Core"); set("material", "Si (Silicon) - Palik"); set("x span", 6e-6); set("y span", 0.5e-6); # 500 nm width set("z min", 0); set("z max", 0.22e-6); # 220 nm height # Set up the FDTD Simulation Solver Region addfdtd; set("dimension", 2); # 3D FDTD set("x span", 5e-6); set("y span", 3e-6); set("z span", 1.3e-6); set("pml layers", 12); # Set up the Mode Source addmode; set("injection axis", "x-axis"); set("direction", "forward"); set("x", -2e-6); set("y span", 2e-6); set("z span", 1e-6); set("center wavelength", 1.55e-6); set("wavelength span", 0.1e-6); # Set up the Transmission Profile Monitor addpower; set("name", "Transmission"); set("monitor type", "2d x-normal"); set("x", 2.2e-6); set("y span", 2e-6); set("z span", 1e-6); Use code with caution. Troubleshooting and Best Practices

After the run, insert a script file ( Script → Edit Script ). Calculate how well a fiber mode couples to your chip

: Placed across a waveguide cross-section to calculate exactly how much power couples into a specific guided mode versus scattering into radiation modes. Step 5: Running the Simulation and Analyzing Results

: Calculate transmission, reflection, and field profiles. Troubleshooting and Best Practices After the run, insert

Some advanced tutorials (like large-area metalenses) require significant RAM or High-Performance Computing (HPC) resources, which can be a barrier for students using standard laptops. Learning Path Recommendation

Lumerical FDTD is not merely a black-box solver; it is an interactive environment that demands the user translate physical intuition into a set of numerical choices—mesh size, boundary conditions, source shape, and monitor placement. Mastering this tool requires both theoretical knowledge of the FDTD method and practical experience with its workflow. By following a disciplined approach—defining the region, constructing the geometry, configuring sources and monitors, refining the mesh, and rigorously testing convergence—a researcher can confidently simulate complex light-matter interactions. From designing meta-lenses and photonic crystals to simulating plasmonic waveguides and solar cells, Lumerical FDTD remains an indispensable bridge between the abstract equations of electromagnetism and the tangible devices of the future.

: To capture transmission, reflection, and electric/magnetic field profiles ( Time-Domain