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
|1||From the Simulation menu, select 2D Simulation Parameters.
The Simulation Parameters dialog box appears.
|2||Type/select the following information:
Mesh Delta X [μm]: 0.05
Mesh Delta Y [μm]: 0.05
The Boundary Conditions dialog box appears.
|4||Type/select the following information (see Figure 107):
-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
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.|