FDTD product reference manual

The FDTD reference manual provides detailed descriptions of product features.

Related resources

• FDTD course: A self paced course intended for beginner to intermediate users with a focus on providing an understanding of the solver physics, simulation workflow and data analysis. The "My first simulation" section is a great getting started tutorial.
• FDTD videos: List of videos from the FDTD course.
• Ansys Learning Forum (Photonics category): A large repository of Q&A content from the Ansys Lumerical community.
• Application Gallery: Find example files, simulation methodologies, and tips to help you get started quickly and easily. You can also browse the Application Gallery directly from within our products in the product launcher.

Solver

Learn about the FDTD solver and related topics

• Finite Difference Time Domain (FDTD) solver introduction
• Understanding ray vs wave optics with a simple example
• Units and normalization
• Frequency domain normalization
• Spectral averaging
• Parseval's theorem - Energy conservation
• Far-field projections
  • Simple example
  • Direction unit vector coordinates
  • Spatial filtering
  • Field polarization
  • Magnetic fields
  • Periodic structures
  • Power integration on hemisphere
  • Creating line plots
  • Projection distance scaling
• Grating projections
  • Periodic structures

Material properties

Learn how to define the material properties that will be used in your simulations.

• Material Database
  • III-V Semiconductor Optical Material Data Tool
• Material Explorer
  • Modifying the Material Fits
• Material Permittivity Models
  • Creating Sampled Data Materials
  • (n,k) Material Model
  • Analytic Material Model
  • Material Conductivity Models
• Anisotropic Materials
  
  • LC Rotation
  • Permittivity Rotation
  • Matrix Transformation
  • Grid Attribute Tips
• Advanced Material Models
• Flexible Material Plugin Framework
• Mesh Order

Simulation objects

These objects are used to model the physical structure, define the solver region, any sources of light or doping/generation regions as well as monitors to collect data. The pages provide detailed descriptions of each simulation object. Simulation objects can be added by clicking on the corresponding icon in the GUI.

Structures

• Primitives: Triangle, Rectangle, Polygon, Circle, Ring, Custom, Surface, Waveguide, Sphere, Pyramid, Planar solid, 2D rectangle, 2D polygon
• Complex structures: Arrays of objects, Rounded corners, Waveguide bends, Sidewall angle, Spiral and helix, Surface roughness, 3D contour
• Layer builder
• Dataset builder
• Extending structures through PML

Groups

• Structure Groups
• Analysis Groups
• Components
• Analysis

Attributes

• Index Perturbation
• Charge to index conversion
• Temperature to index conversion

Simulation

Simulation objects are used to define simulation parameters like boundary conditions and mesh size. More information about the solver algorithms can be found in the Solvers section.

• FDTD solver
• Ports
• Mesh override
• Getting the mesh size
• Mesh refinement
• Mesh refinement options
• Using the non-uniform mesh
• Boundary conditions
  • PML boundary conditions
  • Symmetric and anti-symmetric BCs
  • Bloch boundary conditions
  • Periodic boundary conditions

Import

The import button includes options to import from a variety of formats:

• GDSII
• STL
• Surfaces
• Spatial (n,k) data
• Binary spatial data
• Images
• Liquid crystal from CSV

Sources

• Dipoles
  • Homogeneous materials
  • Non-homogeneous materials
• Plane-wave and Beam
  • Edge effects
  • Angled injection
  • Diffracting plane wave source
  • Beam defined by a pupil function
  • Multifrequency beam calculation
• TFSF
  • Correct usage
  • Cross-sections and normalization
• Integrated mode source
  • Mode analysis
  • Plot and Analysis Options
  • Finding Modes
  • Broadband
  • Angled injection
• Import
  • Custom source profile from monitor data
  • Custom source profile from an equation
• BFAST
• Coherence
• Temporal incoherence
• Changing the source bandwidth
  • Custom time signal
  • Custom spectrum

Monitors

• Refractive index
• Field time
• Movie
• Frequency-domain (profile /power)
• Mode expansion
  • Using Mode Expansion Monitors
• Apodization
• Spectral averaging

Optimizations and sweeps

Learn how to run parameter sweep, optimization, yield analysis, and s-parameter analysis tasks.

• Parameter sweeps
  • Sweep scripting commands
  • Nested Sweeps
  • Running parameter sweeps without the CAD
• Optimization
  • Optimization scripting commands
• Monte Carlo analysis
  • Monte Carlo scripting commands
  • Monte Carlo analysis with spatial correlations
• S-parameter matrix sweep

Result analysis

Learn how to access and analyze simulation data.

Working with the graphical user interface (GUI):

• Analysis and layout modes
  
• Results manager
• Using the data visualizer and figure windows

Analysis groups

• Charge and current measurements
• Curved or angled monitors
• Structure outlines
• Changing the far-field refractive index
• Projections from a monitor box
• Directivity
• Polarization ellipse
• Absorption per unit volume
  
  • Simple method
  • Advanced method
  • Advanced method with multiple materials
  • Divergence of Poynting vector
• Direction of power flow
• Power transmission box
• Effective mode area
• Modal volume

Other analysis

• Using impulse response - response to arbitrary input

Convergence testing

• Convergence testing