fdtdx.setup_sparams_simulation

fdtdx.setup_sparams_simulation(polygons, input_ports, output_ports, wavelength, resolution, max_time, domain_size, background_material=None, pml_layers=10, key=None)

Set up an FDTD simulation scene for S-parameter extraction.

Builds a fully initialised simulation scene containing:

• A background SimulationVolume surrounded by PML absorbing boundaries on all six sides.

• Any GDS-derived ExtrudedPolygon objects placed at their requested positions.

• A ModePlaneSource for every input port.

• A ModeOverlapDetector for every output port.

To compute the full S-matrix, call this function once per input port (each time with a single entry in input_ports) and collect the detector readings.

Parameters:

• polygons (list[tuple[ExtrudedPolygon, tuple[float, float, float]]]) – Pairs of (ExtrudedPolygon, center_offset) where center_offset is the 3-D centre of the polygon in the core coordinate system (metres, origin at the start of the core region). The polygon’s partial_real_shape must be fully specified at construction time (no None entries).

• input_ports (list[PortSpec]) – Ports that receive a ModePlaneSource.

• output_ports (list[PortSpec]) – Ports that receive a ModeOverlapDetector.

• wavelength (float) – Free-space wavelength in metres.

• resolution (float) – Spatial resolution (voxel size) in metres.

• max_time (float) – Total simulation time in seconds.

• domain_size (tuple[float, float, float]) – Size of the core simulation region (excluding PML) as (Lx, Ly, Lz) in metres.

• background_material (Material | None) – Material filling the simulation volume. Defaults to air (Material()).

• pml_layers (int) – Number of PML grid cells added to every face.

• key (Array | None) – JAX random key used by place_objects(). Defaults to PRNGKey(0) when None. Usually not necessary to specify since simulation is deterministic.

Return type:

tuple[ObjectContainer, ArrayContainer, SimulationConfig]

Returns:

A 3-tuple (objects, arrays, config), ready to pass to calculate_sparam().