# ModeSource
Injects current source to excite modal profile on finite extent plane.
# Name
name: Optional name for the source.
# Source Region
Specification of the source region.
# Center + size
Object definition through a center position and size.
center: Center of the object in x, y, and z-directions.
Type: floating-point number
- Unit: m, μm (default), or nm
- Default: (0, 0, 0)
size: Size of the object in x, y, and z-directions.
Use Infinity to define a geometry extending to infinity in both directions along an axis.
Type: floating-point number
- Unit: m, μm (default), or nm
- Constraint: greater than or equal to 0
- Required field
# Bounds
Object definition through minimum and maximum coordinate bounds.
min: Values of the x, y, and z coordinates defining the object lower corner.
Type: floating-point number
- Unit: m, μm (default), or nm
- Required field
max: Values of the x, y, and z coordinates defining the object upper corner.
Type: floating-point number
- Unit: m, μm (default), or nm
- Required field
# Direction
direction: Specifies propagation in the positive or negative direction of the injection axis.
Options:
- +: Propogate in the positive direction of the injection axis
- -: Propogate in the negative direction of the injection axis
Required field
# Number of Frequency Points
num_freqs: Number of points used to approximate the frequency dependence of injected field. A Chebyshev interpolation is used, thus, only a small number of points, i.e., less than 20, is typically sufficient to obtain converged results.
- Unit: unitless
- Constraint: greater than 0
- Default: 1
# Source Time
source_time: Specification of the source time-dependence.
Options:
Required field
# Mode Index
mode_index: Index into the collection of modes returned by mode solver. Specifies which mode to inject using this source.
If larger than num_modes in mode_spec, num_modes in the solver will be set to mode_index + 1.
# Frame
Add a thin frame around the source during the FDTD run to improve the injection quality. The frame is positioned along the primal grid lines so that it aligns with the boundaries of the mode solver used to obtain the source profile.
Options:
- PECFrame: PEC source frame
- None: default
length: The length of the frame, specified as the number of cells along the source injection direction. Avalilable when PECFrame is selected.
Type: integer number
- Unit: unitless
- Constraint: greater than 0
- Default: 2
# Mode Specification
mode_spec: Parameters to feed to mode solver which determine modes measured by monitor.
See: ModeSpec