gplugins.lumerical.write_sparameters_lumerical

gplugins.lumerical.write_sparameters_lumerical(component: ComponentSpec, session: object | None = None, run: bool = True, overwrite: bool = False, dirpath: PathType | None = None, layer_stack: LayerStack | None = None, simulation_settings: SimulationSettingsLumericalFdtd = SimulationSettingsLumericalFdtd(background_material='sio2', port_margin=1.5, port_extension=5.0, mesh_accuracy=2, wavelength_start=1.2, wavelength_stop=1.6, wavelength_points=500, simulation_time=1e-11, simulation_temperature=300, frequency_dependent_profile=True, field_profile_samples=15, distance_monitors_to_pml=0.5, material_name_to_lumerical={'si': 'Si (Silicon) - Palik', 'sio2': 'SiO2 (Glass) - Palik', 'sin': 'Si3N4 (Silicon Nitride) - Phillip'}), material_name_to_lumerical: dict[str, MaterialSpec] | None = None, delete_fsp_files: bool = True, xmargin: float = 0, ymargin: float = 0, xmargin_left: float = 0, xmargin_right: float = 0, ymargin_top: float = 0, ymargin_bot: float = 0, zmargin: float = 1.0, **settings) → np.ndarray

Returns and writes component Sparameters using Lumerical FDTD.

If simulation exists it returns the Sparameters directly unless overwrite=True which forces a re-run of the simulation

Writes Sparameters both in .npz and .DAT (interconnect format) as well as simulation settings in .YAML

In the npz format you can see S12m where m stands for magnitude and S12a where a stands for angle in radians

Your components need to have ports, that will extend over the PML.

For your Fab technology you can overwrite

• simulation_settings

• dirpath

• layerStack

converts gdsfactory units (um) to Lumerical units (m)

Disclaimer: This function tries to extract Sparameters automatically is hard to make a function that will fit all your possible simulation settings. You can use this function for inspiration to create your own.

Parameters:

• component – Component to simulate.

• session – you can pass a session=lumapi.FDTD() or it will create one.

• run – True runs Lumerical, False only draws simulation.

• overwrite – run even if simulation results already exists.

• dirpath – directory to store sparameters in npz. Defaults to active Pdk.sparameters_path.

• layer_stack – contains layer to thickness, zmin and material. Defaults to active pdk.layer_stack.

• simulation_settings – dataclass with all simulation_settings.

• material_name_to_lumerical – alias to lumerical material’s database name or refractive index. translate material name in LayerStack to lumerical’s database name.

• delete_fsp_files – deletes lumerical fsp files after simulation.

• xmargin – left/right distance from component to PML.

• xmargin_left – left distance from component to PML.

• xmargin_right – right distance from component to PML.

• ymargin – left/right distance from component to PML.

• ymargin_top – top distance from component to PML.

• ymargin_bot – bottom distance from component to PML.

• zmargin – thickness for cladding above and below core.

Keyword Arguments:

• background_material – for the background.

• port_margin – on both sides of the port width (um).

• port_height – port height (um).

• port_extension – port extension (um).

• mesh_accuracy – 2 (1: coarse, 2: fine, 3: superfine).

• wavelength_start – 1.2 (um).

• wavelength_stop – 1.6 (um).

• wavelength_points –

• simulation_time –

  19. related to max path length 3e8/2.4*10e-12*1e6 = 1.25mm.

• simulation_temperature – in kelvin (default = 300).

• frequency_dependent_profile – computes mode profiles for different wavelengths.

• field_profile_samples – number of wavelengths to compute field profile.

 top view
      ________________________________
     |                               |
     | xmargin                       | port_extension
     |<------>          port_margin ||<-->
  o2_|___________          _________||_o3
     |           \        /          |
     |            \      /           |
     |             ======            |
     |            /      \           |
  o1_|___________/        \__________|_o4
     |   |                           |
     |   |ymargin                    |
     |   |                           |
     |___|___________________________|

side view
      ________________________________
     |                               |
     |                               |
     |                               |
     |ymargin                        |
     |<---> _____         _____      |
     |     |     |       |     |     |
     |     |     |       |     |     |
     |     |_____|       |_____|     |
     |       |                       |
     |       |                       |
     |       |zmargin                |
     |       |                       |
     |_______|_______________________|

Returns:

Sparameters np.ndarray (wavelengths, o1@0,o1@0, o1@0,o2@0 …)

suffix a for angle in radians and m for module.