Multi-Physics

heat

Run a steady-state thermal simulation of a waveguide cross-section. Requires a ‘3D’ license.

Warning

This function is only available under beta release. Please report any issues or bugs.

Note

Each shape() now accepts an input parameter called heat_only (default: False), which can be used to set additional shapes on top or bottom of the photonic layer stack. For example, common heat_only shapes are the substrate and metal heater layers.

Each shape() also now accepts an input parameter called fem_resolution (default: 500), which is used to refine the triangular mesh within certain shapes.

Every material carries thermal_conductivity (W/m·K), resistivity (Ohm·nm), dn_dT (1/K), and eps_r_dc; the defaults are 1e-10, infinity, 0, and 1.0 where no reliable published value has been entered. See the Material Database page for values and sources.

Parameters:

  • min_angle (float) – Minimum angle for triangular mesh. Smaller values result in a finer mesh, but can prevent the meshing algorithm from converging. Default: 30.

  • boundary_temperature (float) – Fixed temperature boundary condition in ‘K’ set along each perimeter indicated by boundaries. Default: 298.

  • boundaries (list[str]) – ‘top’, ‘bottom’, ‘left’, or ‘right’; Indicates which boundaries are set to the fixed temperature boundary_temperature. Default: [‘bottom’].

  • verbose (bool) – Control the display of the progress bar. Default: True.

  • simulation_name (str) – Simulation name. Default: ‘emode’.

Returns:

A dictionary/struct with the mesh points (p), mesh triangles (t), temperature, thermal_conductivity, and heat_generation arrays. It also includes the boundary_temperature and boundaries settings.

electrostatic

Run a steady-state electrostatic simulation of a waveguide cross-section. Requires a ‘3D’ license.

Warning

This function is only available under beta release. Please report any issues or bugs.

Note

Each shape() also now accepts an input parameter called voltage (default: None), which is set to create electric field sources. Shapes with voltage left as None do not get a voltage boundary condition applied.

Each shape() also now accepts an input parameter called fem_resolution (default: 500), which is used to refine the triangular mesh within certain shapes.

Each material in the EMode material database now has eps_r_dc (relative permittivity at ~1 kHz).

The DC field derived here perturbs the permittivity through each material’s linear electro-optic (Pockels) tensor r (get('<material>')['r'], m/V): \(\Delta(1/n^2)_{ij} = \sum_k r_{ijk} E_k\), then \(\Delta\varepsilon = -\varepsilon \cdot \Delta(1/n^2) \cdot \varepsilon\). FDM() applies this automatically on the next solve (include_static=False to skip it), the same way heat()’s temperature field perturbs the permittivity through dn_dT.

Parameters:

  • min_angle (float) – Minimum angle for triangular mesh. Smaller values result in a finer mesh, but can prevent the meshing algorithm from converging. Default: 30.

  • verbose (bool) – Control the display of the progress bar. Default: True.

  • simulation_name (str) – Simulation name. Default: ‘emode’.

Returns:

A dictionary/struct with the mesh points (p), mesh triangles (t), voltage, eps_dc_grid, the per-element electric field (Ex, Ey, in V/nm), and centroids (element centers, in the optical window’s frame).

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