Simulating Fields in Imported Geometry

[dinelanthony]

I am building some devices using GDSFactory and importing them to MEEP to measure their performance. After a while I was finally able to properly import the gds file, but when I set up a simple simulation and run sim.run(until=2), my code hangs indefinitely.

I saw in a previous post that it could be that my code is trying to load too large of a geometry into memory but the simulation is 2D and relatively small.

Code to recreate the issue:

import meep as mp
import matplotlib.pyplot as plt
mp.quiet()

# Get layers
layers = mp.get_GDSII_layers("coupler_full_test_test.gds")
print("Available layers:", layers)

# Define materials
Si = mp.Medium(epsilon=12)  # Silicon, n ≈ 3.45
SiO2 = mp.Medium(epsilon=2.25)  # Silicon Dioxide, n ≈ 1.5

# Get layer number
layer = int(layers[1]) if len(layers) > 1 else int(layers[0])

# Create GDSII prisms with ACTUAL HEIGHT
gdsii_geometry = mp.GDSII_prisms(
    Si, 
    "coupler_full_test_test.gds",
    layer,
    -0.11,     # zmin (bottom of waveguide)
    0.11       # zmax (top of waveguide) - 220nm total height
)
gdsii_geometry[0].center.x = 0  # Center the geometry
gdsii_geometry[1].center.x = 0  # Center the geometry

print(f"GDSII geometry: {len(gdsii_geometry)} prisms")

# Adjust cell size based on your coupler dimensions
cell_size = mp.Vector3(65, 10)  # x, y
source = [mp.EigenModeSource(
    src=mp.GaussianSource(frequency=0.15, fwidth=0.1),
    center=mp.Vector3(-30, 2.5),
    size=mp.Vector3(0, 2),
    eig_band=1,
)]

sim = mp.Simulation(
    cell_size=cell_size,
    geometry=gdsii_geometry,
    sources=source,
    resolution=20,
    boundary_layers=[mp.PML(1.0)],
    default_material=SiO2,
)

Where coupler_full_test_test.gds was created using:

import gdsfactory as gdf
c = gdf.Component()
coupler = c << gdf.components.coupler_full()
c.add_ports(coupler.ports)
c.pprint_ports()
c.flatten()
c.write_gds('coupler_full_test_test.gds')

I feel like I am missing something very simple but I can't seem to find it.