Port Setting

The section describes port.

Ports can act as a combination of mode source and FDFP monitor. Ports can be used alone or in conjunction with the S-matrix sweep tool to extract the S-parameters for a device by using the mode expansion method.

Select Port button in solver tab to create a Port in Composite viewer, and set more parameters in popped-up editing window.

Port

Add Port

After adding solver, click on Add port on top of software to add a Port in secondary toolbar on right side. A Port group will be automatically added, in which newly added Port will be included.

By default, source port will have a red arrow pointing to incident direction. In the image below, port on the right side represents the source port.

Setting of Port Group

In software simulation, users are supported to customize source port in port group, and only one port can be used as source port at a time.

Name of Port Group

Name in General tab displays Name of the port group.

Source Properties

Source properties are used to set source properties.

• Source port
  Source port tab is used to select an existing port as source port.

Name	Description
As source port	Select an existing port from list as source port.
Incident mode ID #	Display number of incident mode.

• Wavelength/Frequency
  Wavelength/Frequency tab is used to set wavelength and frequency of source port.

For specific wavelength/frequency setting of source, please refer to setting of mode expansion.

Monitor Properties

Monitor properties are used to set monitor properties.

Name	Description
Data type	Record data type, which is Frequency-domain by default. This is a read-only parameter.
Spatial interpolation	Spatial interpolation.
Record data in PML	Record data in PML region.

Component

Name	Description
Components	Electromagnetic field components: Ex, Ey, Ez; Hx, Hy, Hz; Poynting vectors: Px, Py, Pz.

Frequency Sampling

Name	Description
Min sampling per cycle	Minimum amount of sampling per cycle; used to set number of sampling points per cycle, default value of 2.
Desired sampling	A parameter used to control sampling density. It specifies field sampling interval or step size during simulation process.
Nyquist limit	To accurately reconstruct a continuous time signal, signal must be sampled at a rate not less than twice highest frequency of signal being analyzed.
Sampling frequency	Represent number of times a continuous signal is sampled per unit time. Sampling frequency should be at least twice highest frequency of signal being analyzed, to comply with Nyquist limit.
Sample time (per # of dt)	Sampling time; Time interval of sampling during simulation, that is, after how many time steps a sample is taken from field.

Port Setting

General Settings

Name	Description
Name	Customize port name.
Incident axis	Set incident axis of source port (normal of incident plane).
Direction	Specify incident direction of source port, with Forward representing forward propagating and Backward representing backward propagating.
Amplitude	Set amplitude of source port.
Phase shift (degree)	Set phase of source port.

Rotation

Please refer to rotation in mode expansion for Rotation setting.

Multi-frequency Field

Name	Description
Multi-frequency field	Allow solving mode distribution of multiple frequency points. It is recommended to check this tab in broadband simulation projects.
Frequency points	Specify how many frequency points are used to calculate mode distribution. Increasing frequency points will increase simulation time. It is recommended to set fewer frequency points in initial stage of simulation.

Select Mode

Please refer to Select mode in mode expansion for Select mode setting.

Mode Analysis

Click Mode Analysis to enter Mode Analysis page, which allows user to select desired type of mode analysis.

Name	Description
Frequency analysis	Perform a frequency sweep. It can be used to calculate dispersion, loss, etc. that occurs when light propagates through a waveguide.
Bent analysis	Perform a curvature radius sweep of a bent waveguide. It can be used to calculate problems such as the effective index and loss when light propagates in waveguides with different bending radii.

In addition, Mode analysis supports custom analysis.

Data Visualizer

Datasets calculated from simulation are saved in Data visualizer page of port. Data returned by Mode port includes:

Name	Description
Sourcepower	Relation between source power and frequency/wavelength, which is only provided by source port.
E	Relation between electric field and frequency/wavelength.
H	Relation between magnetic field and frequency/wavelength.
P	Relation between Poynting vector and frequency/wavelength.
Power	Relation between power and frequency/wavelength.
T	Relation between transmissivity and frequency/wavelength.

ModeExpansion results in Data visualizer page include following data:

Name	Description
N	Power of mode.
A_forward	Complex transmission coefficient of forward propagating mode.
A_backward	Complex transmission coefficient of backward propagating mode.
T_forward	Transmission power from input port to output port.
T_backward	Transmission power from output port to input port.
S	S parameter.

Case: Multi-mode Interference Coupler

Multi-mode Interference Coupler