OptiFDTD has options to use simplified Periodic Boundary Condition (PBC). It can work with other boundary conditions such as Anisotropic PML, PMC, and PEC. With PBC, you can simulate a simple plane wave simulation, or a periodic layout simulation.

For more information regarding PBC, see the Technical Background.

The following procedure is based on . You can also open the project file Sample09_2D_TE_PBG_Domain_Reduced_Square_Lattice.FDT that can be found in the Sample file folder.

Setting the 2D TE FDTD simulation parameters

Step Action
1 From the Simulation menu, select 2D Simulation Parameters.

The Simulation Parameters dialog box appears.

2 Type/select the following information:

Polarization: TE

Mesh Delta X [μm]: 0.05

Mesh Delta Y [μm]: 0.05

3 Click Advanced….

The Boundary Conditions dialog box appears.

4 Type/select the following information (see Figure 107):

-X: PMC

+X: PMC

-Z: Anisotropic PML

+Z: Anisotropic PML

Anisotropic PML Calculation Parameters

Number of Anisotropic PML Layers: 10

Theoretical Reflection Coefficient: 1.0e-12

Real Anisotropic PML Tensor Parameters: 5.0

Power of Grading Polynomial: 3.5

FDTD - Figure 107 2D simulation parameters

Figure 107: 2D simulation parameters

Note: The rectangular beam with PMC boundaries on the edge realizes the TE plane wave simulation for the periodic structure.
5 In Time Parameters, click Calculate.

The default time step size is calculated.

6 Select Run for 12000 Time Steps (Results Finalized).
7 Select Key Input Information: Input Plane1 and wavelength:1.9.

Note: The input plane’s center wavelength is used for DFT calculations.

8 Click OK to close the Simulation Parameters dialog box without running the simulation, or click Run to start the OptiFDTD Simulator.

Note: Before running the simulation, save the project to a file.

9 Perform the simulation and Post-processing analysis as shown in. You will get the same result as shown in Figure 104.