Index Monitor Setting

This section describes the Index monitor.

In FDTD, use Index monitor to record material data in a specified geometric space.

Select Index monitor from the solver tab, create an Index monitor in the Composite viewer, and set relevant parameters in the automatically pop-up properties editing interface.

Index Monitor Setting

General Setting

General tab is used for general setting of Index monitor.

Data Monitoring

Name	Description
Data type	Record data type, which is Refractive index data by default. This is a read-only parameter.
Spatial interpolation	Select types of spatial interpolation by drop-down: None: No spatial interpolation is performed; record refractive index data at actual locations; Mesh cell: Monitor location is intercepted to the nearest mesh cell.
Record data in PML	Record data in the PML region, which is an advanced setting and not checked by default.
Record surface conductivity	Check to enable the option, and record surface conductivity.

For Index monitor, you can set different Spatial interpolation:

The following images depict refractive index distribution with Spatial interpolation set as None and Mesh cell for Index monitor:

Space Sampling

Name	Description
Per # of dx/dy/dz	Sampling interval in the X/Y/Z directions, i.e., after how many discretization steps a sampling is performed.

Geometric Dimensions

Geometry is the tab for setting geometric dimensions of Index monitor. Please refer to geometric dimensions setting of the monitor.

Wavelength/Frequency

Wavelength/Frequency tab is used to set bandwidth range and number of frequency points for Index monitor.

Base on Source Setting

When Base on source setting is checked, the wavelength/frequency range option on the tab exhibits wavelength/frequency range of the light source, and wavelength/frequency range setting tab is in read-only mode.

When Base on source setting is unchecked, wavelength/frequency range option on the tab can be customized.

• Edit simplified

Edit simplified settings is a simplified way to customize wavelength range for the monitor.

• Edit complicated

Edit complicated settings is a complicated way to customize wavelength/frequency range for the monitor.

Data Visualizer

After completing simulation, view returned results in the Data visualizer of Index monitor. Returned result includes:

• Index: Refractive index data;
• Surface conductivity: Surface conductivity data, only returned if Record surface conductivity is selected on General tab.

In Data visualizer of Index monitor, view refractive index distribution of structure using the following steps:

On Visualizer page, you can perform operations such as selection, plotting, and saving of data. Please refer to Data Visualizer for details.

Case: Silicon-Based Waveguide Microring Resonator Model

The special microring resonator structure in the silicon-based waveguide microring resonator has the function of wavelength selection compared to other waveguide structures. In this case, Index monitor is used to record the spatial refractive index distribution of this structure. For detailed information, please refer to the Silicon-based dual straight waveguide microring resonator model.