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Merge pull request #1 from joelslaby/gmeep_modes
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Multimode simulation with gmeep
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@joelslaby
joelslaby committed Nov 9, 2023
2 parents 5ae9e60 + d0d77bf commit c8055f4
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Showing 4 changed files with 123 additions and 37 deletions.
30 changes: 30 additions & 0 deletions docs/notebooks/meep_01_sparameters.py
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Original file line number Diff line number Diff line change
Expand Up @@ -265,6 +265,36 @@
# %% [markdown]
# As you can see this crossing looks beautiful but is quite **lossy** (9 dB @ 1550 nm)

# %% [markdown]
# ## Multimode Simulations
# You can also simulate structures that source and measure multiple modes. We define the `port_source_modes` as a dictionary with the keys as the source keys and the values as list of mode numbers to output (starting at 0 for TE00). Similarly on the output ports, `port_modes` is a list of modes to measure at every output port.

# %%
c = gf.components.straight(length=5, width=2)
sp = gm.write_sparameters_meep(
c,
run=False,
ymargin_top=3,
ymargin_bot=3,
is_3d=False,
resolution=20,
)

# %%
sp = gm.write_sparameters_meep(
c,
run=True,
ymargin_top=3,
ymargin_bot=3,
is_3d=False,
port_source_names=["o1"],
port_source_modes={"o1": [0, 1]},
port_modes=[0, 1],
resolution=20,
overwrite=False,
)
gm.plot.plot_sparameters(sp, with_simpler_labels=False)

# %% [markdown]
# ## Parallel Simulation (multicore/MPI)
#
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2 changes: 1 addition & 1 deletion gplugins/gmeep/get_meep_geometry.py
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ def get_meep_geometry_from_component(
mp.Prism(
vertices=vertices,
height=height,
sidewall_angle=layer_to_sidewall_angle[layer]
sidewall_angle=np.pi * layer_to_sidewall_angle[layer] / 180
if is_3d
else 0,
material=material,
Expand Down
8 changes: 6 additions & 2 deletions gplugins/gmeep/get_simulation.py
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ def get_simulation(
wavelength_points: int = 50,
dfcen: float = 0.2,
port_source_name: str = "o1",
port_source_mode: int = 0,
port_margin: float = 3,
distance_source_to_monitors: float = 0.2,
port_source_offset: float = 0,
Expand Down Expand Up @@ -185,7 +186,9 @@ def get_simulation(
"Did you passed the correct layer_stack?"
)

t_core = max(layers_thickness)
t_core = sum(
layers_thickness
) # This isn't exactly what we want but I think it's better than max
cell_thickness = tpml + zmargin_bot + t_core + zmargin_top + tpml if is_3d else 0

cell_size = mp.Vector3(
Expand Down Expand Up @@ -243,7 +246,7 @@ def get_simulation(
else mp.GaussianSource(fcen, fwidth=frequency_width),
size=size,
center=center,
eig_band=1,
eig_band=port_source_mode + 1,
eig_parity=mp.NO_PARITY if is_3d else mp.EVEN_Y + mp.ODD_Z,
eig_match_freq=True,
eig_kpoint=-1 * mp.Vector3(x=1).rotate(mp.Vector3(z=1), angle_rad),
Expand Down Expand Up @@ -298,6 +301,7 @@ def get_simulation(
monitors=monitors,
sources=sources,
port_source_name=port_source_name,
port_source_mode=port_source_mode,
initialized=False,
)

Expand Down
120 changes: 86 additions & 34 deletions gplugins/gmeep/write_sparameters_meep.py
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,9 @@ def remove_simulation_kwargs(d: dict[str, Any]) -> dict[str, Any]:
return d


def parse_port_eigenmode_coeff(port_name: str, ports: dict[str, Port], sim_dict: dict):
def parse_port_eigenmode_coeff(
port_name: str, ports: dict[str, Port], sim_dict: dict, port_mode: int = 0
):
"""Returns the coefficients relative to whether the wavevector is entering or \
exiting simulation.
Expand Down Expand Up @@ -98,7 +100,7 @@ def parse_port_eigenmode_coeff(port_name: str, ports: dict[str, Port], sim_dict:

# Get port coeffs
monitor_coeff = sim.get_eigenmode_coefficients(
monitors[port_name], [1], kpoint_func=lambda f, n: kpoint
monitors[port_name], [port_mode + 1], kpoint_func=lambda f, n: kpoint
)

coeff_in = monitor_coeff.alpha[
Expand All @@ -115,6 +117,8 @@ def parse_port_eigenmode_coeff(port_name: str, ports: dict[str, Port], sim_dict:
def write_sparameters_meep(
component: ComponentSpec,
port_source_names: list[str] | None = None,
port_source_modes: dict[str, list] = None,
port_modes: list[int] = None,
port_symmetries: PortSymmetries | None = None,
resolution: int = 30,
wavelength_start: float = 1.5,
Expand All @@ -128,20 +132,26 @@ def write_sparameters_meep(
filepath: Path | None = None,
overwrite: bool = False,
animate: bool = False,
animate_center: tuple = None,
animate_size: tuple = None,
lazy_parallelism: bool = False,
run: bool = True,
dispersive: bool = False,
xmargin: float = 0,
ymargin: float = 3,
ymargin: float = 0,
zmargin: float = 0,
xmargin_left: float = 0,
xmargin_right: float = 0,
ymargin_top: float = 0,
ymargin_bot: float = 0,
zmargin_top: float = 0,
zmargin_bot: float = 0,
decay_by: float = 1e-3,
is_3d: bool = False,
z: float = 0,
plot_args: dict | None = None,
only_return_filepath_sim_settings=False,
verbosity: int = 0,
**settings,
) -> dict[str, np.ndarray]:
r"""Returns Sparameters and writes them to npz filepath.
Expand Down Expand Up @@ -235,6 +245,8 @@ def write_sparameters_meep(
ymargin: top and bottom distance from component to PML.
ymargin_top: north distance from component to PML.
ymargin_bot: south distance from component to PML.
zmargin_top: +z distance from component to PML.
zmargin_bot: -z distance from component to PML.
is_3d: if True runs in 3D (much slower).
z: for 2D plot.
plot_args: if animate or not run, customization keyword arguments passed to
Expand Down Expand Up @@ -282,6 +294,9 @@ def write_sparameters_meep(
ymargin_top = ymargin_top or ymargin
ymargin_bot = ymargin_bot or ymargin

zmargin_top = zmargin_top or zmargin
zmargin_bot = zmargin_bot or zmargin

sim_settings = dict(
resolution=resolution,
port_symmetries=port_symmetries,
Expand All @@ -292,6 +307,8 @@ def write_sparameters_meep(
port_monitor_offset=port_monitor_offset,
port_source_offset=port_source_offset,
dispersive=dispersive,
zmargin_top=zmargin_top,
zmargin_bot=zmargin_bot,
ymargin_top=ymargin_top,
ymargin_bot=ymargin_bot,
xmargin_left=xmargin_left,
Expand Down Expand Up @@ -331,18 +348,34 @@ def write_sparameters_meep(
right=xmargin_right,
)

component_ref = component.ref()
ports = component_ref.ports
port_names = [port.name for port in list(ports.values())]
port_source_names = port_source_names or port_names
port_source_modes = port_source_modes or {key: [0] for key in port_source_names}
port_modes = port_modes or [0]

num_sims = len(port_source_names) - len(port_symmetries)

# set verbosity
mp.verbosity(verbosity)

if not run:
sim_dict = get_simulation(
component=component,
wavelength_start=wavelength_start,
wavelength_stop=wavelength_stop,
wavelength_points=wavelength_points,
layer_stack=layer_stack,
port_source_name=port_source_names[0],
port_margin=port_margin,
port_monitor_offset=port_monitor_offset,
port_source_offset=port_source_offset,
dispersive=dispersive,
is_3d=is_3d,
resolution=resolution,
zmargin_top=zmargin_top,
zmargin_bot=zmargin_bot,
**settings,
)
sim = sim_dict["sim"]
Expand All @@ -365,12 +398,6 @@ def write_sparameters_meep(
elif overwrite:
filepath.unlink()

component_ref = component.ref()
ports = component_ref.ports
port_names = [port.name for port in list(ports.values())]
port_source_names = port_source_names or port_names
num_sims = len(port_source_names) - len(port_symmetries)

sp = {} # Sparameters dict
start = time.time()

Expand All @@ -380,10 +407,13 @@ def sparameter_calculation(
component: Component,
port_symmetries: PortSymmetries | None = port_symmetries,
port_names: list[str] = port_names,
port_source_mode: int = 0,
wavelength_start: float = wavelength_start,
wavelength_stop: float = wavelength_stop,
wavelength_points: int = wavelength_points,
animate: bool = animate,
animate_center: tuple = animate_center,
animate_size: tuple = animate_size,
plot_args: dict = plot_args,
dispersive: bool = dispersive,
decay_by: float = decay_by,
Expand All @@ -393,6 +423,7 @@ def sparameter_calculation(
sim_dict = get_simulation(
component=component,
port_source_name=port_source_name,
port_source_mode=port_source_mode,
resolution=resolution,
wavelength_start=wavelength_start,
wavelength_stop=wavelength_stop,
Expand Down Expand Up @@ -425,34 +456,53 @@ def sparameter_calculation(
if "eps_parameters" not in plot_args:
plot_args["eps_parameters"] = {"contour": True}
if "fields" not in plot_args:
plot_args["fields"] = mp.Ez
if is_3d:
plot_args["fields"] = mp.Hz
else:
plot_args["fields"] = mp.Ez
if "realtime" not in plot_args:
plot_args["realtime"] = True
if "normalize" not in plot_args:
plot_args["normalize"] = True

sim.use_output_directory()
animate = mp.Animate2D(
sim,
**plot_args,
)
if is_3d:
animate = mp.Animate2D(
sim,
output_plane=mp.Volume(
center=mp.Vector3(*animate_center),
size=mp.Vector3(*animate_size),
),
**plot_args,
)
else:
animate = mp.Animate2D(
sim,
**plot_args,
)
sim.run(mp.at_every(1, animate), until_after_sources=termination)
animate.to_mp4(30, f"{component.name}_{port_source_name}.mp4")
animate.to_mp4(
30, f"{component.name}_{port_source_name}_{port_source_mode}.mp4"
)
else:
sim.run(until_after_sources=termination)

# Calculate mode overlaps
# Get source monitor results
source_entering, _ = parse_port_eigenmode_coeff(
port_source_name, component.ports, sim_dict
port_source_name, component.ports, sim_dict, port_mode=port_source_mode
)
# Get coefficients
for port_name in port_names:
_, monitor_exiting = parse_port_eigenmode_coeff(
port_name, component.ports, sim_dict
)
key = f"{port_name}@0,{port_source_name}@0"
sp[key] = monitor_exiting / source_entering
for port_mode in port_modes:
_, monitor_exiting = parse_port_eigenmode_coeff(
port_name,
component.ports,
sim_dict,
port_mode=port_mode,
)
key = f"{port_name}@{port_mode},{port_source_name}@{port_source_mode}"
sp[key] = monitor_exiting / source_entering

if bool(port_symmetries):
for key, symmetries in port_symmetries.items():
Expand All @@ -462,7 +512,7 @@ def sparameter_calculation(

return sp

if lazy_parallelism:
if lazy_parallelism: # TODO: FIX Port modes
from mpi4py import MPI

cores = min([num_sims, multiprocessing.cpu_count()])
Expand Down Expand Up @@ -507,19 +557,21 @@ def sparameter_calculation(

else:
for port_source_name in tqdm(port_source_names):
sp.update(
sparameter_calculation(
port_source_name,
component=component,
port_symmetries=port_symmetries,
wavelength_start=wavelength_start,
wavelength_stop=wavelength_stop,
wavelength_points=wavelength_points,
animate=animate,
port_names=port_names,
**settings,
for port_source_mode in port_source_modes[port_source_name]:
sp.update(
sparameter_calculation(
port_source_name,
port_source_mode=port_source_mode,
component=component,
port_symmetries=port_symmetries,
wavelength_start=wavelength_start,
wavelength_stop=wavelength_stop,
wavelength_points=wavelength_points,
animate=animate,
port_names=port_names,
**settings,
)
)
)
sp["wavelengths"] = np.linspace(
wavelength_start, wavelength_stop, wavelength_points
)
Expand Down

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