def main(save_folder: str,
min_feature: float = 100,
sim_3d: bool = False,
visualize: bool = False) -> None:
goos.util.setup_logging(save_folder)
with goos.OptimizationPlan(save_path=save_folder) as plan:
wg_in = goos.Cuboid(pos=goos.Constant([-2000, 0, 0]),
extents=goos.Constant([3000, 400, 220]),
material=goos.material.Material(index=3.45))
wg_out = goos.Cuboid(pos=goos.Constant([0, 2000, 0]),
extents=goos.Constant([400, 3000, 220]),
material=goos.material.Material(index=3.45))
def initializer(size):
return np.random.random(size) * 0.2 + 0.5
# Continuous optimization.
var, design = goos.cubic_param_shape(
initializer=initializer,
pos=goos.Constant([0, 0, 0]),
extents=[2000, 2000, 220],
pixel_spacing=40,
control_point_spacing=1.5 * min_feature,
material=goos.material.Material(index=1),
material2=goos.material.Material(index=3.45),
var_name="var_cont")
sigmoid_factor = goos.Variable(4, parameter=True, name="discr_factor")
design = goos.cast(goos.Sigmoid(sigmoid_factor * (2 * design - 1)),
goos.Shape)
eps = goos.GroupShape([wg_in, wg_out, design])
# This node is purely for debugging purposes.
eps_rendered = maxwell.RenderShape(
design,
region=goos.Box3d(center=[0, 0, 0], extents=[3000, 3000, 0]),
mesh=maxwell.UniformMesh(dx=40),
wavelength=1550,
)
if visualize:
goos.util.visualize_eps(eps_rendered.get().array[2])
obj, sim = make_objective_fdtd(eps, "cont", sim_3d=sim_3d)
for factor in [4, 8]:
sigmoid_factor.set(factor)
goos.opt.scipy_minimize(
obj,
"L-BFGS-B",
monitor_list=[sim["eps"], sim["field"], sim["overlap"], obj],
max_iters=6,
name="opt_cont{}".format(factor))
plan.save()
plan.run()
if visualize:
goos.util.visualize_eps(eps_rendered.get().array[2])
def test_render_pixelated_cont_shape():
with goos.OptimizationPlan() as plan:
def initializer(size):
return [[1, 0], [0.5, 0.75], [0, 0.8], [1, 0.8]]
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([200, 0, 0]),
extents=[1000, 1000, 220],
material=goos.material.Material(index=2),
material2=goos.material.Material(index=4),
pixel_size=[250, 500, 220])
rect = goos.Cuboid(extents=goos.Constant([1000, 1000, 220]),
pos=goos.Constant([200, 0, 0]),
material=goos.material.Material(index=2))
render = maxwell.RenderShape(
design,
region=goos.Box3d(center=[0, 0, 0], extents=[1500, 1500, 200]),
mesh=maxwell.UniformMesh(dx=40),
background=goos.material.Material(index=1.0),
wavelength=1550)
np.testing.assert_almost_equal(
np.real(render.get().array[2][10:, 8, 3]), [
1., 8.5, 16., 16., 16., 16., 16., 14.5, 10., 10., 10., 10.,
10., 10., 4., 4., 4., 4., 4., 4., 13., 16., 16., 16., 16., 16.,
8.5
])
def test_render_prism():
with goos.OptimizationPlan() as plan:
rect = goos.Cuboid(extents=goos.Constant([80, 80, 100]),
pos=goos.Constant([0, 0, 0]),
material=goos.material.Material(index=3.45))
render = maxwell.RenderShape(
rect,
region=goos.Box3d(center=[0, 0, 0], extents=[160, 200, 40]),
mesh=maxwell.UniformMesh(dx=40),
background=goos.material.Material(index=1.0),
wavelength=1550)
np.testing.assert_array_almost_equal(
render.get().array,
[[[[1.], [1.], [1.], [1.], [1.]],
[[1.], [1.], [11.9025], [11.9025], [1.]],
[[1.], [1.], [11.9025], [11.9025], [1.]],
[[1.], [1.], [1.], [1.], [1.]]],
[[[1.], [1.], [1.], [1.], [1.]],
[[1.], [3.725625], [6.45125], [3.725625], [1.]],
[[1.], [6.45125], [11.9025], [6.45125], [1.]],
[[1.], [3.725625], [6.45125], [3.725625], [1.]]],
[[[1.], [1.], [1.], [1.], [1.]],
[[1.], [1.], [6.45125], [6.45125], [1.]],
[[1.], [1.], [11.9025], [11.9025], [1.]],
[[1.], [1.], [6.45125], [6.45125], [1.]]]])
def main(save_folder: str, visualize: bool = False) -> None:
goos.util.setup_logging(save_folder)
params = Options()
with goos.OptimizationPlan(save_path=save_folder) as plan:
substrate = goos.Cuboid(
pos=goos.Constant([
params.coupler_len / 2, 0,
-params.box_size - params.wg_thickness / 2 - 5000
]),
extents=goos.Constant([params.coupler_len + 10000, 1000, 10000]),
material=goos.material.Material(index=params.eps_wg))
waveguide = goos.Cuboid(
pos=goos.Constant([-params.wg_len / 2, 0, 0]),
extents=goos.Constant(
[params.wg_len, params.wg_width, params.wg_thickness]),
material=goos.material.Material(index=params.eps_wg))
wg_bottom = goos.Cuboid(
pos=goos.Constant([
params.coupler_len / 2, 0,
-params.wg_thickness / 2 * params.etch_frac
]),
extents=goos.Constant([
params.coupler_len, params.wg_width,
params.wg_thickness * (1 - params.etch_frac)
]),
material=goos.material.Material(index=params.eps_wg))
def initializer(size):
return np.random.random(size)
# Continuous optimization.
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([
params.coupler_len / 2, 0,
params.wg_thickness / 2 * (1 - params.etch_frac)
]),
extents=[
params.coupler_len, params.wg_width,
params.wg_thickness * params.etch_frac
],
material=goos.material.Material(index=params.eps_bg),
material2=goos.material.Material(index=params.eps_wg),
pixel_size=[
params.pixel_size, params.wg_width, params.wg_thickness
])
obj, sim = make_objective(
goos.GroupShape([substrate, waveguide, wg_bottom, design]), "cont",
params)
goos.opt.scipy_minimize(
obj,
"L-BFGS-B",
monitor_list=[sim["eps"], sim["field"], sim["overlap"], obj],
max_iters=60,
name="opt_cont")
# Prevent optimization from optimizing over continuous variable.
var.freeze()
# Run discretization.
grating_var, height_var, design_disc = goos.grating.discretize_to_pixelated_grating(
var,
height_fracs=[0, 1],
pixel_size=params.pixel_size,
start_height_ind=1,
end_height_ind=1,
min_features=params.min_features,
pos=[
params.coupler_len / 2, 0,
params.wg_thickness / 2 * (1 - params.etch_frac)
],
extents=[
params.coupler_len, params.wg_width,
params.wg_thickness * params.etch_frac
],
material=goos.material.Material(index=params.eps_bg),
material2=goos.material.Material(index=params.eps_wg),
grating_dir=0,
grating_dir_spacing=20,
etch_dir=2,
etch_dir_divs=1)
obj, sim = make_objective(
goos.GroupShape([substrate, waveguide, wg_bottom, design_disc]),
"disc", params)
goos.opt.scipy_minimize(
obj,
"L-BFGS-B",
monitor_list=[sim["eps"], sim["field"], sim["overlap"], obj],
max_iters=100,
name="opt_disc",
ftol=1e-8)
plan.save()
plan.run()
if visualize:
goos.util.visualize_eps(sim["eps"].get().array[2])
# the following line and set `out_folder_name` somewhere else.
out_folder_name = "bend90_" + datetime.datetime.now().strftime("%Y%m%d-%H%M%S")
out_folder = os.path.join(os.getcwd(), out_folder_name)
if (not os.path.exists(out_folder)):
os.makedirs(out_folder)
## Setup logging and Optimization Plan. ##
plan = goos.OptimizationPlan(save_path=out_folder)
'''
Define the constant background structures that will not be changed
during the design. In this case, these are the input and output waveguides.
'''
with plan:
# Define input waveguide.
wg_in = goos.Cuboid(pos=goos.Constant([-2000, 0, 0]),
extents=goos.Constant([3000, 400, 220]),
material=goos.material.Material(index=1))
# Define output waveguide.
wg_out = goos.Cuboid(pos=goos.Constant([0, 2000, 0]),
extents=goos.Constant([400, 3000, 220]),
material=goos.material.Material(index=1))
# Group these background structures together.
eps_background_structures = goos.GroupShape([wg_in, wg_out])
'''
Visualize the constant background structures we just defined.
'''
with plan:
eps_rendered = maxwell.RenderShape(
eps_background_structures,
region=goos.Box3d(center=[0, 0, 0], extents=[3000, 3000, 0]),
def test_simulate_wg_straight_2d_multicore():
with goos.OptimizationPlan() as plan:
eps = goos.Cuboid(pos=goos.Constant([0, 0, 0]),
extents=goos.Constant([6000, 500, 40]),
material=goos.material.Material(index=3.45))
sim = meep.FdtdSimulation(
eps=eps,
sources=[
meep.WaveguideModeSource(
center=[-500, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1,
wavelength=1550,
bandwidth=100,
),
],
sim_space=meep.SimulationSpace(
dx=20,
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 0],
),
pml_thickness=[800, 800, 800, 800, 0, 0]),
sim_timing=meep.SimulationTiming(stopping_conditions=[
meep.StopWhenFieldsDecayed(
time_increment=50,
component=2,
pos=[0, 0, 0],
threshold=1e-6,
)
]),
background=goos.material.Material(index=1.0),
outputs=[
meep.Epsilon(wavelength=1550),
meep.ElectricField(wavelength=1550),
meep.WaveguideModeOverlap(wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
meep.WaveguideModeOverlap(wavelength=1550,
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[-1, 0, 0],
mode_num=0,
power=1),
meep.WaveguideModeOverlap(wavelength=1550,
center=[0, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
meep.WaveguideModeOverlap(wavelength=1500,
center=[0, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1,
normalize=True),
meep.WaveguideModeOverlap(wavelength=1500,
center=[0, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1,
normalize=False),
],
sim_cores=2,
)
out = sim.get()
# Plot the fields.
#import matplotlib.pyplot as plt
#eps = out[0].array
#plt.imshow(eps)
#plt.figure()
#field = out[1].array
#plt.imshow(np.real(field[2]))
#plt.show()
# Power transmitted should be unity but numerical dispersion could
# affect the actual transmitted power. Last time we checked, the power
# ~0.96.
# 1550 nm overlap.
assert np.abs(out[4].array)**2 >= 0.96
assert np.abs(out[4].array)**2 <= 1.04
# 1525 nm overlap (with normalization)
assert np.abs(out[5].array)**2 >= 0.96
assert np.abs(out[5].array)**2 <= 1.04
# The unnormalized power should be roughly ~30%.
assert np.abs(out[6].array)**2 < 0.40
assert np.abs(out[6].array)**2 > 0.20
# Check that waveguide power is roughly constant along waveguide.
np.testing.assert_allclose(np.abs(out[2].array)**2,
np.abs(out[4].array)**2,
rtol=1e-2)
# Check that we get minimal leakage of power flowing backwards.
assert np.abs(out[3].array)**2 / np.abs(out[2].array)**2 < 0.01
def test_simulate_wg_opt():
with goos.OptimizationPlan() as plan:
wg_in = goos.Cuboid(pos=goos.Constant([-2000, 0, 0]),
extents=goos.Constant([3000, 800, 40]),
material=goos.material.Material(index=3.45))
wg_out = goos.Cuboid(pos=goos.Constant([2000, 0, 0]),
extents=goos.Constant([3000, 800, 40]),
material=goos.material.Material(index=3.45))
def initializer(size):
# Set the seed immediately before calling `random` to ensure
# reproducibility.
np.random.seed(247)
return np.random.random(size) * 0.1 + np.ones(size) * 0.7
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([0, 0, 0]),
extents=[1000, 800, 40],
pixel_size=[40, 40, 40],
material=goos.material.Material(index=1),
material2=goos.material.Material(index=3.45),
)
eps = goos.GroupShape([wg_in, wg_out, design])
sim = meep.FdtdSimulation(
eps=eps,
sources=[
meep.WaveguideModeSource(
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=2,
power=1,
wavelength=1550,
bandwidth=100,
)
],
sim_space=meep.SimulationSpace(
dx=40,
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 0],
),
pml_thickness=[400, 400, 400, 400, 0, 0]),
sim_timing=meep.SimulationTiming(stopping_conditions=[
meep.StopWhenFieldsDecayed(
time_increment=50,
component=2,
pos=[0, 0, 0],
threshold=1e-6,
)
], ),
background=goos.material.Material(index=1.0),
outputs=[
meep.Epsilon(wavelength=1550),
meep.ElectricField(wavelength=1550),
meep.WaveguideModeOverlap(wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
])
obj = -goos.abs(sim[2])
import meep as mp
mp.quiet()
goos.opt.scipy_minimize(obj,
"L-BFGS-B",
monitor_list=[obj],
max_iters=5)
plan.run()
# Check that we can optimize. We choose something over 60% as
# incorrect gradients will typically not reach this point.
assert obj.get().array < -0.85
# As a final check, compare simulation results against Maxwell.
# Note that dx = 40 for Meep is actually too innaccurate. We therefore
# resimulate the final structure for both Meep and Maxwell.
from spins.goos_sim import maxwell
sim_fdfd = maxwell.fdfd_simulation(
wavelength=1550,
eps=eps,
sources=[
maxwell.WaveguideModeSource(
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=2,
power=1,
)
],
simulation_space=maxwell.SimulationSpace(
mesh=maxwell.UniformMesh(dx=20),
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 0],
),
pml_thickness=[400, 400, 400, 400, 0, 0]),
background=goos.material.Material(index=1.0),
outputs=[
maxwell.Epsilon(),
maxwell.ElectricField(),
maxwell.WaveguideModeOverlap(center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
],
solver="local_direct")
sim_fdtd_hi = meep.FdtdSimulation(
eps=eps,
sources=[
meep.WaveguideModeSource(
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=2,
power=1,
wavelength=1550,
bandwidth=100,
)
],
sim_space=meep.SimulationSpace(
dx=20,
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 0],
),
pml_thickness=[400, 400, 400, 400, 0, 0]),
sim_timing=meep.SimulationTiming(stopping_conditions=[
meep.StopWhenFieldsDecayed(
time_increment=50,
component=2,
pos=[0, 0, 0],
threshold=1e-6,
)
], ),
background=goos.material.Material(index=1.0),
outputs=[
meep.Epsilon(wavelength=1550),
meep.ElectricField(wavelength=1550),
meep.WaveguideModeOverlap(wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
])
fdtd_hi_power = goos.abs(sim_fdtd_hi[2])**2
fdfd_power = goos.abs(sim_fdfd[2])**2
# Check that power is correct within 0.5%.
assert np.abs(fdfd_power.get().array - fdtd_hi_power.get().array) < 0.005
def main(save_folder: str,
min_feature: float = 100,
use_cubic: bool = True,
visualize: bool = False) -> None:
goos.util.setup_logging(save_folder)
with goos.OptimizationPlan(save_path=save_folder) as plan:
wg_1 = goos.Cuboid(pos=goos.Constant([1600, -4500, 0]),
extents=goos.Constant([600, 1000, 230]),
material=goos.material.Material(index=3.45))
wg_2 = goos.Cuboid(pos=goos.Constant([-1600, -4500, 0]),
extents=goos.Constant([600, 1000, 230]),
material=goos.material.Material(index=3.45))
wg_3 = goos.Cuboid(pos=goos.Constant([1600, 4500, 0]),
extents=goos.Constant([600, 1000, 230]),
material=goos.material.Material(index=3.45))
wg_4 = goos.Cuboid(pos=goos.Constant([-1600, 4500, 0]),
extents=goos.Constant([600, 1000, 230]),
material=goos.material.Material(index=3.45))
wg_5 = goos.Cuboid(pos=goos.Constant([4500, -1600, 0]),
extents=goos.Constant([1000, 600, 230]),
material=goos.material.Material(index=3.45))
wg_6 = goos.Cuboid(pos=goos.Constant([4500, 1600, 0]),
extents=goos.Constant([1000, 600, 230]),
material=goos.material.Material(index=3.45))
wg_7 = goos.Cuboid(pos=goos.Constant([-4500, 0, 0]),
extents=goos.Constant([1000, 600, 230]),
material=goos.material.Material(index=3.45))
substrate = goos.Cuboid(pos=goos.Constant([0, 0, -500]),
extents=goos.Constant([11000, 11000, 770]),
material=goos.material.Material(index=1.4))
def initializer(size):
# Set the seed immediately before calling `random` to ensure
# reproducibility.
#np.random.seed(247)
return np.ones(size) * 0.5
#return np.random.random(size) * 0.2 + 0.5
# Continuous optimization.
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([0, 0, 0]),
extents=[8000, 8000, 230],
material=goos.material.Material(index=1),
material2=goos.material.Material(index=3.45),
pixel_size=[50, 50, 230],
var_name="var_cont")
sigmoid_factor = goos.Variable(4, parameter=True, name="discr_factor")
design = goos.cast(goos.Sigmoid(sigmoid_factor * (2 * design - 1)),
goos.Shape)
eps = goos.GroupShape(
[wg_1, wg_2, wg_3, wg_4, wg_5, wg_6, wg_7, design, substrate])
# This node is purely for debugging purposes.
eps_rendered = maxwell.RenderShape(
eps,
region=goos.Box3d(center=[0, 0, 0], extents=[10000, 10000, 0]),
mesh=maxwell.UniformMesh(dx=50),
wavelength=635,
)
if visualize:
goos.util.visualize_eps(eps_rendered.get().array[2])
obj, sim1, sim2, sim3, sim4, sim5, sim6, sim7 = make_objective(
eps, "cont")
for factor in [4, 8, 12]:
sigmoid_factor.set(factor)
goos.opt.scipy_minimize(
obj,
"L-BFGS-B",
monitor_list=[
sim1["eps"], sim1["field"], sim1["overlap1"],
sim1["overlap2"], sim1["overlap3"], sim1["overlap4"],
sim1["overlap5"], sim1["overlap6"], sim1["overlap7"],
sim2["eps"], sim2["field"], sim2["overlap1"],
sim2["overlap2"], sim2["overlap3"], sim2["overlap4"],
sim2["overlap5"], sim2["overlap6"], sim2["overlap7"],
sim3["eps"], sim3["field"], sim3["overlap1"],
sim3["overlap2"], sim3["overlap3"], sim3["overlap4"],
sim3["overlap5"], sim3["overlap6"], sim3["overlap7"],
sim4["eps"], sim4["field"], sim4["overlap1"],
sim4["overlap2"], sim4["overlap3"], sim4["overlap4"],
sim4["overlap5"], sim4["overlap6"], sim4["overlap7"],
sim5["eps"], sim5["field"], sim5["overlap1"],
sim5["overlap2"], sim5["overlap3"], sim5["overlap4"],
sim5["overlap5"], sim5["overlap6"], sim5["overlap7"],
sim6["eps"], sim6["field"], sim6["overlap1"],
sim6["overlap2"], sim6["overlap3"], sim6["overlap4"],
sim6["overlap5"], sim6["overlap6"], sim6["overlap7"],
sim7["eps"], sim7["field"], sim7["overlap1"],
sim7["overlap2"], sim7["overlap3"], sim7["overlap4"],
sim7["overlap5"], sim7["overlap6"], sim7["overlap7"], obj
],
max_iters=25,
name="opt_cont{}".format(factor))
plan.save()
plan.run()
if visualize:
goos.util.visualize_eps(eps_rendered.get().array[2])
def test_simulate_wg_opt():
with goos.OptimizationPlan() as plan:
wg_in = goos.Cuboid(pos=goos.Constant([-2000, 0, 0]),
extents=goos.Constant([3000, 800, 220]),
material=goos.material.Material(index=3.45))
wg_out = goos.Cuboid(pos=goos.Constant([2000, 0, 0]),
extents=goos.Constant([3000, 800, 220]),
material=goos.material.Material(index=3.45))
def initializer(size):
# Set the seed immediately before calling `random` to ensure
# reproducibility.
np.random.seed(247)
return np.random.random(size) * 0.1 + np.ones(size) * 0.5
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([0, 0, 0]),
extents=[1000, 800, 220],
pixel_size=[40, 40, 40],
material=goos.material.Material(index=1),
material2=goos.material.Material(index=3.45),
)
eps = goos.GroupShape([wg_in, wg_out, design])
sim = maxwell.fdfd_simulation(
eps=eps,
wavelength=1550,
solver="local_direct",
sources=[
maxwell.WaveguideModeSource(
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=2,
power=1,
)
],
simulation_space=maxwell.SimulationSpace(
mesh=maxwell.UniformMesh(dx=40),
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 40],
),
pml_thickness=[400, 400, 400, 400, 0, 0]),
background=goos.material.Material(index=1.0),
outputs=[
maxwell.Epsilon(),
maxwell.ElectricField(),
maxwell.WaveguideModeOverlap(wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
])
obj = -goos.abs(sim[2])
goos.opt.scipy_minimize(obj,
"L-BFGS-B",
monitor_list=[obj],
max_iters=15)
plan.run()
assert obj.get().array < -0.90
def test_simulate_wg_opt_grad():
with goos.OptimizationPlan() as plan:
wg_in = goos.Cuboid(pos=goos.Constant([-2000, 0, 0]),
extents=goos.Constant([3000, 800, 220]),
material=goos.material.Material(index=3.45))
wg_out = goos.Cuboid(pos=goos.Constant([2000, 0, 0]),
extents=goos.Constant([3000, 800, 220]),
material=goos.material.Material(index=3.45))
def initializer(size):
# Set the seed immediately before calling `random` to ensure
# reproducibility.
np.random.seed(247)
return np.random.random(size)
var, design = goos.pixelated_cont_shape(
initializer=initializer,
pos=goos.Constant([0, 0, 0]),
extents=[1000, 800, 220],
pixel_size=[500, 400, 220],
material=goos.material.Material(index=1),
material2=goos.material.Material(index=3.45),
)
eps = goos.GroupShape([wg_in, wg_out, design])
sim = maxwell.fdfd_simulation(
eps=eps,
wavelength=1550,
solver="local_direct",
sources=[
maxwell.WaveguideModeSource(
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=2,
power=1,
)
],
simulation_space=maxwell.SimulationSpace(
mesh=maxwell.UniformMesh(dx=40),
sim_region=goos.Box3d(
center=[0, 0, 0],
extents=[4000, 4000, 40],
),
pml_thickness=[400, 400, 400, 400, 0, 0]),
background=goos.material.Material(index=1.0),
outputs=[
maxwell.Epsilon(),
maxwell.ElectricField(),
maxwell.WaveguideModeOverlap(wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
])
obj = -goos.abs(sim[2])
adjoint_grad = obj.get_grad([var])[0].array_grad
# Calculate brute force gradient.
var_val = var.get().array
eps = 0.001
num_grad = np.zeros_like(var_val)
for i in range(var_val.shape[0]):
for j in range(var_val.shape[1]):
temp_val = var_val.copy()
temp_val[i, j] += eps
var.set(temp_val)
fplus = obj.get(run=True).array
temp_val = var_val.copy()
temp_val[i, j] -= eps
var.set(temp_val)
fminus = obj.get(run=True).array
num_grad[i, j] = (fplus - fminus) / (2 * eps)
np.testing.assert_array_almost_equal(adjoint_grad, num_grad, decimal=3)
def test_simulate_2d():
with goos.OptimizationPlan() as plan:
sim_region = goos.Box3d(center=[0, 0, 0], extents=[4000, 4000, 40])
sim_mesh = maxwell.UniformMesh(dx=40)
waveguide = goos.Cuboid(pos=goos.Constant([0, 0, 0]),
extents=goos.Constant([6000, 500, 40]),
material=goos.material.Material(index=3.45))
eps = maxwell.RenderShape(waveguide,
region=sim_region,
mesh=sim_mesh,
background=goos.material.Material(index=1.0),
wavelength=1550)
sim = maxwell.SimulateNode(
wavelength=1550,
simulation_space=maxwell.SimulationSpace(
sim_region=sim_region,
mesh=sim_mesh,
pml_thickness=[400, 400, 400, 400, 0, 0],
),
eps=eps,
sources=[
maxwell.WaveguideModeSource(
center=[-500, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1,
)
],
solver_info=maxwell.DirectSolver(),
outputs=[
maxwell.Epsilon(name="eps"),
maxwell.ElectricField(name="fields"),
maxwell.WaveguideModeOverlap(name="overlap_forward",
wavelength=1550,
center=[1000, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
maxwell.WaveguideModeOverlap(name="overlap_backward",
wavelength=1550,
center=[-1000, 0, 0],
extents=[0, 2500, 0],
normal=[-1, 0, 0],
mode_num=0,
power=1),
maxwell.WaveguideModeOverlap(name="overlap_forward2",
wavelength=1550,
center=[0, 0, 0],
extents=[0, 2500, 0],
normal=[1, 0, 0],
mode_num=0,
power=1),
])
out = sim.get()
# Power transmitted should be unity but numerical dispersion could
# affect the actual transmitted power.
assert np.abs(out[4].array)**2 >= 0.99
assert np.abs(out[4].array)**2 <= 1.01
# Check that waveguide power is roughly constant along waveguide.
np.testing.assert_allclose(np.abs(out[2].array)**2,
np.abs(out[4].array)**2,
rtol=1e-2)
# Check that we get minimal leakage of power flowing backwards.
assert np.abs(out[3].array)**2 < 0.01