def test_mv_mult(self):
lattice = mp.Lattice(size=mp.Vector3(1, 7),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
res = lattice.basis * mp.Vector3(1)
exp = mp.Vector3(0.8660254037844388, 0.5000000000000001)
self.assertTrue(res.close(exp))
def test_geometric_objects_lattice_duplicates(self):
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 7),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(
math.sqrt(3) / 2, -0.5))
eps = 12
r = 0.2
geometry = [mp.Cylinder(r, material=mp.Medium(epsilon=eps))]
geometry = mp.geometric_objects_lattice_duplicates(
geometry_lattice, geometry)
med = mp.Medium(epsilon=12)
expected = [
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=3.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=2.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=1.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=0.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=-1.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=-2.0)),
mp.Cylinder(0.2, material=med, center=mp.Vector3(y=-3.0)),
]
for exp, res in zip(expected, geometry):
self.assertEqual(exp.center, res.center)
self.assertEqual(exp.radius, res.radius)
def get_freqs_interpolate(hx=0.24, hy=0.24, a=0.33, wy=0.7, h=0.22):
'''
Useless
'''
import meep as mp
from meep import mpb
mode = "zEyO"
resolution = 20 # pixels/a, taken from simpetus example
a = round(a, 3) # units of um
h = round(h, 3) # units of um
w = round(wy, 3) # units of um
hx = round(hx, 3)
hy = round(hy, 3)
h = h / a # units of "a"
w = w / a # units of "a"
hx = hx / a # units of "a"
hy = hy / a # units of "a"
nSi = 3.45
Si = mp.Medium(index=nSi)
geometry_lattice = mp.Lattice(size=mp.Vector3(
1, 4, 4)) # dimensions of lattice taken from simpetus example
geometry = [
mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf, w, h),
material=Si),
mp.Ellipsoid(material=mp.air,
center=mp.Vector3(),
size=mp.Vector3(hx, hy, mp.inf))
]
num_k = 20 # from simpetus example, no. of k_points to evaluate the eigen frequency at
k_points = mp.interpolate(
num_k,
[mp.Vector3(0, 0, 0), mp.Vector3(0.5, 0, 0)])
num_bands = 2 # from simpetus example
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=resolution,
num_bands=num_bands)
if mode == "te":
ms.run_te() # running for all modes and extracting parities
if mode == "zEyO":
ms.run_yodd_zeven()
return ms.freqs
def test_rotate_reciprocal(self):
axis = mp.Vector3(1)
v = mp.Vector3(2, 2, 2)
lattice = mp.Lattice(size=mp.Vector3(1, 1))
res = v.rotate_reciprocal(axis, 3, lattice)
self.assertTrue(
res.close(mp.Vector3(2.0, -2.262225009320625,
-1.6977449770811563)))
def get_freqs(hx=0.24, hy=0.24, a=0.33, w=0.7, h=0.22):
'''
Returns tuple of dielectric and air band edge frequencies for input parameters
'''
import meep as mp
from meep import mpb
res = 20
mode = "zEyO"
resolution = res # pixels/a, taken from simpetus example
a = round(a, 3) # units of um
h = round(h, 3) # units of um
w = round(w, 3) # units of um
hx = round(hx, 3)
hy = round(hy, 3)
h = h / a # units of "a"
w = w / a # units of "a"
hx = hx / a # units of "a"
hy = hy / a # units of "a"
nSi = 3.45
Si = mp.Medium(index=nSi)
geometry_lattice = mp.Lattice(size=mp.Vector3(
1, 4, 4)) # dimensions of lattice taken from simpetus example
geometry = [
mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf, w, h),
material=Si),
mp.Ellipsoid(material=mp.air,
center=mp.Vector3(),
size=mp.Vector3(hx, hy, mp.inf))
]
k_points = [mp.Vector3(0.5, 0, 0)]
num_bands = 2 # from simpetus example
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=resolution,
num_bands=num_bands)
if mode == "te":
ms.run_te() # running for all modes and extracting parities
if mode == "zEyO":
ms.run_yodd_zeven()
return ms.freqs
def test_basis(self):
lattice = mp.Lattice(size=mp.Vector3(1, 7),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
b = lattice.basis
exp = mp.Matrix(mp.Vector3(0.8660254037844388, 0.5000000000000001),
mp.Vector3(0.8660254037844388, -0.5000000000000001),
mp.Vector3(z=1.0))
for e, r in zip([exp.c1, exp.c2, exp.c3], [b.c1, b.c2, b.c3]):
self.assertTrue(e.close(r))
def test_point_defect_state(self):
ms = self.init_solver()
ms.geometry_lattice = mp.Lattice(size=mp.Vector3(5, 5))
ms.geometry = [mp.Cylinder(0.2, material=mp.Medium(epsilon=12))]
ms.geometry = mp.geometric_objects_lattice_duplicates(
ms.geometry_lattice, ms.geometry)
ms.geometry.append(mp.Cylinder(0.2, material=mp.air))
ms.resolution = 16
ms.k_points = [mp.Vector3(0.5, 0.5)]
ms.num_bands = 50
ms.run_tm()
mpb.fix_efield_phase(ms, 25)
mpb.output_efield_z(ms, 25)
mpb.fix_dfield_phase(ms, 25)
ms.get_dfield(25)
ms.compute_field_energy()
c = mp.Cylinder(1.0, material=mp.air)
e = ms.compute_energy_in_objects([c])
self.assertAlmostEqual(0.6227482574427817, e, places=3)
ms.num_bands = 1
ms.target_freq = (0.2812 + 0.4174) / 2
ms.tolerance = 1e-8
ms.run_tm()
expected_brd = [
((0.37730041222979477, mp.Vector3(0.5, 0.5, 0.0)),
(0.37730041222979477, mp.Vector3(0.5, 0.5, 0.0))),
]
self.check_band_range_data(expected_brd, ms.band_range_data)
old_geometry = ms.geometry # save the 5x5 grid with a missing rod
def rootfun(eps):
ms.geometry = old_geometry + [
mp.Cylinder(0.2, material=mp.Medium(epsilon=eps))
]
ms.run_tm()
return ms.get_freqs()[0] - 0.314159
rooteps = ridder(rootfun, 1, 12)
rootval = rootfun(rooteps)
self.assertAlmostEqual(5.288830111797463, rooteps, places=3)
self.assertAlmostEqual(9.300716530269426e-9, rootval, places=3)
def test_inverse(self):
self.matrix_eq(self.identity, self.identity.inverse())
lattice = mp.Lattice(size=mp.Vector3(1, 7),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
res = lattice.basis.inverse()
exp = mp.Matrix(mp.Vector3(0.5773502691896256, 0.5773502691896256, -0.0),
mp.Vector3(0.9999999999999998, -0.9999999999999998, -0.0),
mp.Vector3(-0.0, -0.0, 1.0))
self.matrix_close(exp, res)
def get_freqs(hx, hy, a, w):
wz = 0.22
res = 20
mode = "zEyO"
resolution = res # pixels/a, taken from simpetus example
# a = round(a,3) # units of um
# h = round(wz, 3) # units of um
# w = round(wy, 3) # units of um
# hx = round(hx, 3)
# hy = round(hy, 3)
h = wz
h = h / a # units of "a"
w = w / a # units of "a"
hx = hx / a # units of "a"
hy = hy / a # units of "a"
nSi = 3.45
Si = mp.Medium(index=nSi)
geometry_lattice = mp.Lattice(size=mp.Vector3(
1, 4, 4)) # dimensions of lattice taken from simpetus example
geometry = [
mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf, w, h),
material=Si),
mp.Ellipsoid(material=mp.air,
center=mp.Vector3(),
size=mp.Vector3(hx, hy, mp.inf))
]
k_points = [mp.Vector3(0.5, 0, 0)]
num_bands = 2 # from simpetus example
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=resolution,
num_bands=num_bands)
if mode == "te":
ms.run_te() # running for all modes and extracting parities
if mode == "zEyO":
ms.run_yodd_zeven()
return ms.freqs
def test_triangular_lattice(self):
expected_brd = [
((0.0, mp.Vector3(0.0, 0.0,
0.0)), (0.2746902258623623,
mp.Vector3(-0.3333333333333333,
0.3333333333333333, 0.0))),
((0.44533108084715683, mp.Vector3(0.0, 0.5, 0.0)),
(0.5605181423162835, mp.Vector3(0.0, 0.0, 0.0))),
((0.4902389149027666,
mp.Vector3(-0.3333333333333333, 0.3333333333333333,
0.0)), (0.5605607947797747, mp.Vector3(0.0, 0.0,
0.0))),
((0.5932960873585144, mp.Vector3(0.0, 0.0, 0.0)),
(0.7907195974443698,
mp.Vector3(-0.3333333333333333, 0.3333333333333333, 0.0))),
((0.790832076332758,
mp.Vector3(-0.3333333333333333, 0.3333333333333333,
0.0)), (0.8374511167537562, mp.Vector3(0.0, 0.0,
0.0))),
((0.8375948528443267, mp.Vector3(0.0, 0.0, 0.0)),
(0.867200926490345, mp.Vector3(-0.2, 0.39999999999999997, 0.0))),
((0.8691349955739203,
mp.Vector3(-0.13333333333333336, 0.4333333333333333,
0.0)), (0.9941291022664892, mp.Vector3(0.0, 0.0,
0.0))),
((0.8992499095547049,
mp.Vector3(-0.3333333333333333, 0.3333333333333333,
0.0)), (1.098318352915696, mp.Vector3(0.0, 0.0,
0.0))),
]
ms = self.init_solver()
ms.geometry_lattice = mp.Lattice(
size=mp.Vector3(1, 1),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
k_points = [
mp.Vector3(),
mp.Vector3(y=0.5),
mp.Vector3(-1 / 3, 1 / 3),
mp.Vector3()
]
ms.k_points = mp.interpolate(4, k_points)
ms.run_tm()
self.check_band_range_data(expected_brd, ms.band_range_data)
def example_case():
num_bands = 3
resolution = 32
k_point = [
mp.Vector3(),
mp.Vector3(0.5),
mp.Vector3(0.5, 0.5),
mp.Vector3()
]
k_points = mp.interpolate(40, k_point)
geometry = [mp.Cylinder(0.2, material=mp.Medium(epsilon=12))]
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 1))
ms = mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry=geometry,
geometry_lattice=geometry_lattice,
resolution=resolution)
ms.run_te()
return ms
def init_solver(self, geom=True):
num_bands = 8
k_points = [
mp.Vector3(),
mp.Vector3(0.5),
mp.Vector3(0.5, 0.5),
mp.Vector3()
]
geometry = [mp.Cylinder(0.2, material=mp.Medium(
epsilon=12))] if geom else []
k_points = mp.interpolate(4, k_points)
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 1))
resolution = 32
return mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry=geometry,
geometry_lattice=geometry_lattice,
resolution=resolution,
filename_prefix=self.filename_prefix,
deterministic=True,
tolerance=1e-12)
import re import subprocess ## Parametres de maille n_lo = 1 n_hi = 3.25 Nbands = 16 ra = 0.20 resolution = 64 ## Definition discretisation traits horizontaux nbr_points_x = 4 nbr_points_y = 4 ## Repere direct carree 45 geometry_lattice = mp.Lattice() geometry_lattice.basis_size = mp.Vector3(1, 1, 1) geometry_lattice.size = mp.Vector3(1, 1, 0) geometry_lattice.basis1 = mp.Vector3(math.sqrt(2) / 2, -math.sqrt(2) / 2) geometry_lattice.basis2 = mp.Vector3(math.sqrt(2) / 2, +math.sqrt(2) / 2) ## Definition motif default_material = mp.Medium(index=n_hi) C_0 = [mp.Cylinder(ra, material=mp.Medium(index=n_lo))] ## Limites IBZ REPERE RECIPROQUE k_point_gamma = mp.Vector3(0, 0) k_point_M_rec = mp.Vector3(1 / 2, 1 / 2) k_point_K_rec = mp.Vector3(1 / 2, 0) k_point_K_cart = mp.Vector3(math.sqrt(2) / 2, 0) k_point_M_cart = mp.Vector3(math.sqrt(2) / 4, math.sqrt(2) / 4)
# -*- coding: utf-8 -*-
import meep as mp
from meep import mpb
import numpy as np
import matplotlib.pyplot as plt
resolution = 128 # pixels/μm
Si = mp.Medium(index=3.45)
syz = 10
geometry_lattice = mp.Lattice(size=mp.Vector3(0,syz,syz))
k_points = [mp.Vector3(0.5)]
a = 1.0 # waveguide width
def parallel_waveguide(s,yodd):
geometry = [mp.Block(center=mp.Vector3(0,-0.5*(s+a),0),
size=mp.Vector3(mp.inf,a,a),
material=Si),
mp.Block(center=mp.Vector3(0,0.5*(s+a),0),
size=mp.Vector3(mp.inf,a,a),
material=Si)]
ms = mpb.ModeSolver(resolution=resolution,
k_points=k_points,
geometry_lattice=geometry_lattice,
geometry=geometry,
num_bands=1,
def get_mode_solver_rib(
wg_width: float = 0.45,
wg_thickness: float = 0.22,
slab_thickness: int = 0.0,
ncore: float = 3.47,
nclad: float = 1.44,
sy: float = 2.0,
sz: float = 2.0,
res: int = 32,
nmodes: int = 4,
) -> mpb.ModeSolver:
"""Returns a mode_solver simulation.
Args:
wg_width: wg_width (um)
wg_thickness: wg height (um)
slab_thickness: thickness for the waveguide slab
ncore: core material refractive index
nclad: clad material refractive index
sy: simulation region width (um)
sz: simulation region height (um)
res: resolution (pixels/um)
nmodes: number of modes
"""
material_core = mp.Medium(index=ncore)
material_clad = mp.Medium(index=nclad)
# Define the computational cell. We'll make x the propagation direction.
# the other cell sizes should be big enough so that the boundaries are
# far away from the mode field.
geometry_lattice = mp.Lattice(size=mp.Vector3(0, sy, sz))
# define the 2d blocks for the strip and substrate
geometry = [
mp.Block(
size=mp.Vector3(mp.inf, mp.inf, mp.inf),
material=material_clad,
),
# uncomment this for air cladded waveguides
# mp.Block(
# size=mp.Vector3(mp.inf, mp.inf, 0.5 * (sz - wg_thickness)),
# center=mp.Vector3(z=0.25 * (sz + wg_thickness)),
# material=material_clad,
# ),
mp.Block(
size=mp.Vector3(mp.inf, mp.inf, slab_thickness),
material=material_core,
center=mp.Vector3(z=-0.5 * slab_thickness),
),
mp.Block(
size=mp.Vector3(mp.inf, wg_width, wg_thickness),
material=material_core,
center=mp.Vector3(z=0),
),
]
# The k (i.e. beta, i.e. propagation constant) points to look at, in
# units of 2*pi/um. We'll look at num_k points from k_min to k_max.
num_k = 9
k_min = 0.1
k_max = 3.0
k_points = mp.interpolate(num_k, [mp.Vector3(k_min), mp.Vector3(k_max)])
# Increase this to see more modes. (The guided ones are the ones below the
# light line, i.e. those with frequencies < kmag / 1.45, where kmag
# is the corresponding column in the output if you grep for "freqs:".)
# use this prefix for output files
filename_prefix = tmp / f"rib_{wg_width}_{wg_thickness}_{slab_thickness}"
mode_solver = mpb.ModeSolver(
geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=res,
num_bands=nmodes,
filename_prefix=str(filename_prefix),
)
mode_solver.nmodes = nmodes
return mode_solver
def main(args):
"""
Args:
* **res** (int): Resolution of the simulation [pixels/um] (default=10)
* **wavelength** (float): Wavelength in microns (default=1.55)
* **sx** (float): Size of the simulation region in the x-direction (default=4.0)
* **sy** (float): Size of the simulation region in the y-direction (default=4.0)
* **plot_mode_number** (int): Which mode to plot (only plots one mode at a time). Must be a number equal to or less than num_mode (default=1)
* **polarization** (string): If true, outputs the fields at the relevant waveguide cross-sections (top-down and side-view)
* **epsilon_file** (string): Filename with the dielectric "block" objects (default=None)
* **output_directory** (string): If true, outputs the fields at the relevant waveguide cross-sections (top-down and side-view)
* **save_mode_data** (boolean): Save the mode image and data to a separate file (default=None)
* **suppress_window** (boolean): Suppress the matplotlib window (default=False)
"""
#Boolean inputs
save_mode_data = args.save_mode_data
suppress_window = args.suppress_window
#String inputs
polarization = args.polarization
epsilon_file = args.epsilon_file
output_directory = args.output_directory
if not os.path.exists(output_directory):
os.makedirs(output_directory)
#Int inputs
res = args.res
# num_modes = args.num_modes
plot_mode_number = args.plot_mode_number
#Float inputs
wavelength = args.wavelength
sx = args.sx
sy = args.sy
geometry_lattice = mp.Lattice(size=mp.Vector3(0, sy, sx))
with h5py.File(epsilon_file, 'r') as hf:
data = np.array([
np.array(hf.get("CX")),
np.array(hf.get("CY")),
np.array(hf.get("width_list")),
np.array(hf.get("height_list")),
np.array(hf.get("eps_list"))
])
geometry = []
for i in range(len(data[0])):
geometry.append(
mp.Block(size=mp.Vector3(mp.inf, data[3][i], data[2][i]),
center=mp.Vector3(0, data[1][i], data[0][i]),
material=mp.Medium(epsilon=data[4][i])))
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
geometry=geometry,
resolution=res,
default_material=mp.Medium(epsilon=1.0),
num_bands=plot_mode_number)
freq = 1 / wavelength
kdir = mp.Vector3(1, 0, 0)
tol = 1e-6
kmag_guess = freq * 2.02
kmag_min = freq * 0.01
kmag_max = freq * 10.0
if polarization == "TE":
parity = mp.ODD_Z
elif polarization == "TM":
parity = mp.EVEN_Z
elif polarization == "None":
parity = mp.NO_PARITY
k = ms.find_k(parity, freq, plot_mode_number, plot_mode_number, kdir, tol,
kmag_guess, kmag_min, kmag_max)
vg = ms.compute_group_velocities()
print('k=' + str(k))
print('v_g=' + str(vg))
k = k[0]
vg = vg[0][0]
""" Plot modes """
eps = ms.get_epsilon()
ms.get_dfield(plot_mode_number)
E = ms.get_efield(plot_mode_number)
Eabs = np.sqrt(
np.multiply(E[:, :, 0, 2], E[:, :, 0, 2]) +
np.multiply(E[:, :, 0, 1], E[:, :, 0, 1]) +
np.multiply(E[:, :, 0, 0], E[:, :, 0, 0]))
H = ms.get_hfield(plot_mode_number)
Habs = np.sqrt(
np.multiply(H[:, :, 0, 2], H[:, :, 0, 2]) +
np.multiply(H[:, :, 0, 1], H[:, :, 0, 1]) +
np.multiply(H[:, :, 0, 0], H[:, :, 0, 0]))
plt_extent = [-sy / 2.0, +sy / 2.0, -sx / 2.0, +sx / 2.0]
cmap_fields = 'hot_r'
cmap_geom = 'viridis'
if not suppress_window:
"""
First plot electric field
"""
plt.figure(figsize=(14, 8))
plt.subplot(2, 3, 1)
plt.imshow(abs(E[:, :, 0, 2]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_x|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 2)
plt.imshow(abs(E[:, :, 0, 1]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_y|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 3)
plt.imshow(abs(E[:, :, 0, 0]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_z|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 4)
plt.imshow(abs(Eabs),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 5)
plt.imshow(eps,
cmap=cmap_geom,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide dielectric")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.tight_layout()
plt.show()
"""
Then plot magnetic field
"""
plt.figure(figsize=(14, 8))
plt.subplot(2, 3, 1)
plt.imshow(abs(H[:, :, 0, 2]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_x|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 2)
plt.imshow(abs(H[:, :, 0, 1]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_y|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 3)
plt.imshow(abs(H[:, :, 0, 0]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_z|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 4)
plt.imshow(abs(Habs),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 5)
plt.imshow(eps,
cmap=cmap_geom,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide dielectric")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.tight_layout()
plt.show()
if save_mode_data:
"""
First plot electric field
"""
plt.figure(figsize=(14, 8))
plt.subplot(2, 3, 1)
plt.imshow(abs(E[:, :, 0, 2]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_x|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 2)
plt.imshow(abs(E[:, :, 0, 1]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_y|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 3)
plt.imshow(abs(E[:, :, 0, 0]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E_z|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 4)
plt.imshow(abs(Eabs),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|E|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 5)
plt.imshow(eps,
cmap=cmap_geom,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide dielectric")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.tight_layout()
if polarization == "TE":
savetxt = '%s/TE_mode%d_Efield.png' % (output_directory,
plot_mode_number)
elif polarization == "TM":
savetxt = '%s/TM_mode%d_Efield.png' % (output_directory,
plot_mode_number)
elif polarization == "None":
savetxt = '%s/mode%d_Efield.png' % (output_directory,
plot_mode_number)
plt.savefig(savetxt)
"""
Then plot magnetic field
"""
plt.figure(figsize=(14, 8))
plt.subplot(2, 3, 1)
plt.imshow(abs(H[:, :, 0, 2]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_x|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 2)
plt.imshow(abs(H[:, :, 0, 1]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_y|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 3)
plt.imshow(abs(H[:, :, 0, 0]),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H_z|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 4)
plt.imshow(abs(Habs),
cmap=cmap_fields,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide mode $|H|$")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.subplot(2, 3, 5)
plt.imshow(eps,
cmap=cmap_geom,
origin='lower',
aspect='auto',
extent=plt_extent)
plt.title("Waveguide dielectric")
plt.ylabel("y-axis")
plt.xlabel("x-axis")
plt.colorbar()
plt.tight_layout()
if polarization == "TE":
savetxt = '%s/TE_mode%d_Hfield.png' % (output_directory,
plot_mode_number)
elif polarization == "TM":
savetxt = '%s/TM_mode%d_Hfield.png' % (output_directory,
plot_mode_number)
elif polarization == "None":
savetxt = '%s/mode%d_Hfield.png' % (output_directory,
plot_mode_number)
plt.savefig(savetxt)
"""
Save the mode data to a .txt file
"""
if polarization == "TE":
datafilename = '%s/TE_mode%d_data.txt' % (output_directory,
plot_mode_number)
elif polarization == "TM":
datafilename = '%s/TM_mode%d_data.txt' % (output_directory,
plot_mode_number)
elif polarization == "None":
datafilename = '%s/mode%d_data.txt' % (output_directory,
plot_mode_number)
f = open(datafilename, 'w')
f.write(
'#################################################################\n'
)
f.write('Mode %d with %s polarization \n' %
(plot_mode_number, polarization))
f.write(
'#################################################################\n'
)
f.write('\n')
f.write('k \t\t %0.6f \n' % (k))
f.write('n_eff \t\t %0.6f \n' % (wavelength * k))
f.write('vg \t\t %0.6f \n' % (vg))
f.write('ng \t\t %0.6f \n' % (1 / vg))
def test_cartesian_to_lattice(self):
lattice = mp.Lattice(size=mp.Vector3(1, 7),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
res = mp.cartesian_to_lattice(lattice.basis * mp.Vector3(1), lattice)
self.assertEqual(res, mp.Vector3(1))
# The index will vary sinusoidally between index-min and index-max:
index_min = 1
index_max = 3
# Define a function of position p (in the lattice basis) that returns
# the material at that position. In this case, we use the function:
# index-min + 0.5 * (index-max - index-min)
# * (1 + cos(2*pi*x))
# This is periodic, and also has inversion symmetry.
def eps_func(p):
return mp.Medium(index=index_min + 0.5 * (index_max - index_min) *
(1 + math.cos(2 * math.pi * p.x)))
geometry_lattice = mp.Lattice(size=mp.Vector3(1)) # 1d cell
# We'll just make it the default material, so that it goes everywhere.
default_material = eps_func
k_points = mp.interpolate(9, [mp.Vector3(), mp.Vector3(x=0.5)])
resolution = 32
num_bands = 8
ms = mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry_lattice=geometry_lattice,
resolution=resolution,
default_material=default_material)
height=mp.inf,
material=mp.Medium(epsilon=(0.001 * int(sys.argv[5]))**2))
]
# mp.Cylinder(radius = 0.001*int(sys.argv[2]), center = mp.Vector3( 0, 0), material=mp.Medium(epsilon=(0.001*int(sys.argv[4]))**2))
# geometry = [mp.Cylinder(, center = mp.Vector3( 1/3, 1/3), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[1]), center = mp.Vector3( 1/3, 0), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[1]), center = mp.Vector3( 0,-1/3), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[1]), center = mp.Vector3(-1/3,-1/3), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[1]), center = mp.Vector3(-1/3, 0), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[1]), center = mp.Vector3( 0, 1/3), material=mp.Medium(epsilon=1)),
# mp.Cylinder(radius = 0.001*int(sys.argv[2]), center = mp.Vector3( 0, 0), material=mp.Medium(epsilon=(0.001*int(sys.argv[4]))**2))]
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 1),
basis1=mp.Vector3(0.5, 3**0.5 / 2),
basis2=mp.Vector3(0.5, -3**0.5 / 2))
ms = mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry_lattice=geometry_lattice,
geometry=geometry,
resolution=resolution,
default_material=mp.Medium(epsilon=(0.001 *
int(sys.argv[3]))**2))
ms.run_te()
md = mpb.MPBData(rectify=True, periods=2, resolution=128)
eps = ms.get_epsilon()
converted_eps = md.convert(eps)
mp.Vector3(0.5, 0, 0),
mp.Vector3(0.5, 0.1, 0.0),
mp.Vector3(0.5, 0.2, 0.0),
mp.Vector3(0.5, 0.3, 0.0),
mp.Vector3(0.5, 0.4, 0.0),
mp.Vector3(0.5, 0.5, 0),
mp.Vector3(0.4, 0.4, 0.0),
mp.Vector3(0.3, 0.3, 0.0),
mp.Vector3(0.2, 0.2, 0.0),
mp.Vector3(0.1, 0.1, 0.0),
mp.Vector3(0, 0, 0)
]
geometry = [mp.Cylinder(0.2, material=mp.Medium(epsilon=12))]
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 1))
resolution = 32
ms = mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry=geometry,
geometry_lattice=geometry_lattice,
resolution=resolution)
#import sys
#sys.exit(0)
#print_heading("Square lattice of rods: TE bands")
ms.run_te()
def __init__(self,
resolution=10,
is_negative_epsilon_ok=False,
eigensolver_flops=0,
eigensolver_flags=68,
use_simple_preconditioner=False,
force_mu=False,
mu_input_file='',
epsilon_input_file='',
mesh_size=3,
target_freq=0.0,
tolerance=1.0e-7,
num_bands=1,
k_points=[],
ensure_periodicity=True,
geometry=[],
geometry_lattice=mp.Lattice(),
geometry_center=mp.Vector3(0, 0, 0),
default_material=mp.Medium(epsilon=1),
dimensions=3,
random_fields=False,
filename_prefix='',
deterministic=False,
verbose=False,
optimize_grid_size=True,
eigensolver_nwork=3,
eigensolver_block_size=-11):
self.mode_solver = None
self.resolution = resolution
self.eigensolver_flags = eigensolver_flags
self.k_points = k_points
self.geometry = geometry
self.geometry_lattice = geometry_lattice
self.geometry_center = mp.Vector3(*geometry_center)
self.default_material = default_material
self.random_fields = random_fields
self.filename_prefix = filename_prefix
self.optimize_grid_size = optimize_grid_size
self.parity = ''
self.iterations = 0
self.all_freqs = None
self.freqs = []
self.band_range_data = []
self.total_run_time = 0
self.current_k = mp.Vector3()
self.k_split_num = 1
self.k_split_index = 0
self.eigensolver_iters = []
grid_size = self._adjust_grid_size()
if type(self.default_material) is not mp.Medium and callable(
self.default_material):
init_do_averaging(self.default_material)
self.default_material.eps = False
self.mode_solver = mode_solver(
num_bands,
self.resolution,
self.geometry_lattice,
tolerance,
mesh_size,
self.default_material,
deterministic,
target_freq,
dimensions,
verbose,
ensure_periodicity,
eigensolver_flops,
is_negative_epsilon_ok,
epsilon_input_file,
mu_input_file,
force_mu,
use_simple_preconditioner,
grid_size,
eigensolver_nwork,
eigensolver_block_size,
)
hu = min(hu, (H - h) / 2)
hl = min(hl, (H - h) / 2)
n_m = max(n_x, n_y, n_z)
n_c = max(n_l, n_u)
fcen = 1 / wavelength
df = 0.05
default_material = mp.Medium(epsilon=1)
upper_material = mp.Medium(epsilon=n_u**2)
core_material = mp.Medium(epsilon_diag=mp.Vector3(n_x**2, n_y**2, n_z**2))
lower_material = mp.Medium(epsilon=n_l**2)
geometry_lattice = mp.Lattice(size=mp.Vector3(0, monitorheight, 0))
# bandNum = 4
# geometry = [mp.Block(mp.Vector3(mp.inf, h, mp.inf), center=mp.Vector3(0,0,0), material=core_material),
# mp.Block(mp.Vector3(mp.inf, h, mp.inf), center=mp.Vector3(0,0,0), material=core_material),
# mp.Block(mp.Vector3(mp.inf, h, mp.inf), center=mp.Vector3(0,0,0), material=core_material),
# mp.Block(mp.Vector3(mp.inf, h, mp.inf), center=mp.Vector3(0,0,0), material=core_material)]
geometrympb = [
mp.Block(mp.Vector3(mp.inf, monitorheight, mp.inf),
center=mp.Vector3(0, 0),
material=default_material),
mp.Block(mp.Vector3(mp.inf, hu + h / 2, mp.inf),
center=mp.Vector3(0, (hu + h / 2) / 2),
material=upper_material),
eps0Si = 7.98737492
epsLorentzSi = 3.68799143
omega0Si = 3.93282466e15
epsSi = lambda lam: eps0Si + epsLorentzSi * omega0Si**2 / (omega0Si**2 - (
2 * np.pi * c * 1e6 / lam)**2)
# Silicon Dioxide dispersion relation
eps0SiO2 = 2.119881
epsLorentzSiO2 = 49.43721
omega0SiO2 = 3.309238e13
epsSiO2 = lambda lam: eps0SiO2 + epsLorentzSiO2 * omega0SiO2**2 / (
omega0SiO2**2 - (2 * np.pi * c * 1e6 / lam)**2)
sc_y = 2 # supercell width (um)
sc_z = 2 # supercell height (um)
geometry_lattice = mp.Lattice(size=mp.Vector3(0, sc_y, sc_z))
resolution = 32 # pixels/um
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
resolution=resolution,
ensure_periodicity=False)
# ------------------------------------------------------------------------------ #
# Loop through experiment
# ------------------------------------------------------------------------------ #
# get current frequency and wavelength
currentLambda = 1.55
omegaIn = 1 / currentLambda
# Update material parameters
# Our First Band Structure
print_heading("Square lattice of rods in air")
num_bands = 8
k_points = [
mp.Vector3(), # Gamma
mp.Vector3(0.5), # X
mp.Vector3(0.5, 0.5), # M
mp.Vector3()
] # Gamma
k_points = mp.interpolate(4, k_points)
geometry = [mp.Cylinder(0.2, material=mp.Medium(epsilon=12))]
geometry_lattice = mp.Lattice(size=mp.Vector3(1, 1))
resolution = 32
ms = mpb.ModeSolver(num_bands=num_bands,
k_points=k_points,
geometry=geometry,
geometry_lattice=geometry_lattice,
resolution=resolution)
print_heading("Square lattice of rods: TE bands")
ms.run_te()
print_heading("Square lattice of rods: TM bands")
ms.run_tm()
print_heading("Square lattice of rods: TM, w/efield")
def __init__(self,
resolution=10,
is_negative_epsilon_ok=False,
eigensolver_flops=0,
is_eigensolver_davidson=False,
eigensolver_nwork=3,
eigensolver_block_size=-11,
eigensolver_flags=68,
is_simple_preconditioner=False,
is_deterministic=False,
force_mu=False,
mu_input_file='',
epsilon_input_file='',
mesh_size=3,
target_freq=0.0,
tolerance=1.0e-7,
num_bands=1,
k_points=[],
ensure_periodicity=True,
geometry=[],
geometry_lattice=mp.Lattice(),
geometry_center=mp.Vector3(0, 0, 0),
default_material=mp.Medium(epsilon=1),
dimensions=3,
random_fields=False,
filename_prefix='',
deterministic=False,
verbose=False):
self.resolution = resolution
self.is_negative_epsilon_ok = is_negative_epsilon_ok
self.eigensolver_flops = eigensolver_flops
self.is_eigensolver_davidson = is_eigensolver_davidson
self.eigensolver_nwork = eigensolver_nwork
self.eigensolver_block_size = eigensolver_block_size
self.eigensolver_flags = eigensolver_flags
self.is_simple_preconditioner = is_simple_preconditioner
self.is_deterministic = is_deterministic
self.force_mu = force_mu
self.mu_input_file = mu_input_file
self.epsilon_input_file = epsilon_input_file
self.mesh_size = mesh_size
self.target_freq = target_freq
self.tolerance = tolerance
self.num_bands = num_bands
self.k_points = k_points
self.ensure_periodicity = ensure_periodicity
self.geometry = geometry
self.geometry_lattice = geometry_lattice
self.geometry_center = geometry_center
self.default_material = default_material
self.dimensions = dimensions
self.random_fields = random_fields
self.filename_prefix = filename_prefix
self.deterministic = deterministic
self.verbose = verbose
self.parity = ''
self.iterations = 0
self.all_freqs = None
self.freqs = []
self.band_range_data = []
self.eigensolver_flops = 0
self.total_run_time = 0
self.current_k = mp.Vector3()
self.k_split_num = 1
self.k_split_index = 0
self.eigensolver_iters = []
self.mode_solver = None
def get_freqs(hx,
hy,
a,
w,
h=0.22,
substrate=False,
output_epsilon=False,
mode="zEyO",
num_bands=2):
# h = 0.23 # for manually setting waveguide height
res = 20
#mode = "zEyO"
resolution = res # pixels/a, taken from simpetus example
print(" h = " + str(h) + ", SUBSTRATE = " + str(substrate) + ", mode = " +
str(mode))
a = round(a, 3) # units of um
h = round(h, 3) # units of um
w = round(w, 3) # units of um
hx = round(hx, 3)
hy = round(hy, 3)
h = h / a # units of "a"
w = w / a # units of "a"
hx = hx / a # units of "a"
hy = hy / a # units of "a"
cell_x = 1
cell_y = 4
cell_z = 4
nSi = 3.45
Si = mp.Medium(index=nSi)
geometry_lattice = mp.Lattice(size=mp.Vector3(
cell_x, cell_y,
cell_z)) # dimensions of lattice taken from simpetus example
geometry = [
mp.Block(center=mp.Vector3(),
size=mp.Vector3(mp.inf, w, h),
material=Si),
mp.Ellipsoid(material=mp.air,
center=mp.Vector3(),
size=mp.Vector3(hx, hy, mp.inf))
]
if substrate:
geometry = add_substrate(geom=geometry,
waveguide_height=h,
substrate_height=cell_z / 2 -
h / 2) # substrate height normalized with a
k_points = [mp.Vector3(0.5, 0, 0)]
num_bands = num_bands
ms = mpb.ModeSolver(geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=resolution,
num_bands=num_bands)
if mode == "te":
ms.run_te() # running for all modes and extracting parities
if mode == "zEyO":
ms.run_yodd_zeven()
if mode == "yO":
ms.run_yodd()
if mode == "yE":
ms.run_yeven()
# if output_epsilon:
# visualise_geometry(ms = ms, x = None , y = None, z = (4 * res)/ 2, value = None)
if output_epsilon:
return ms.get_epsilon()
# with h5py.File('epsilon.hdf5', 'w') as f:
# arr = ms.get_epsilon
# dset = f.create_dataset("epsilon", data = arr)
return ms.freqs
import math
import meep as mp
from meep import mpb
# Dielectric spheres in a diamond (fcc) lattice. This file is used in
# the "Data Analysis Tutorial" section of the MPB manual.
sqrt_half = math.sqrt(0.5)
sqrt_third = math.sqrt(1.0 / 3.0)
geometry_lattice = mp.Lattice(basis_size=mp.Vector3(sqrt_third, sqrt_third,
sqrt_third),
basis1=mp.Vector3(-1, 1, 1),
basis2=mp.Vector3(1, -1, 1),
basis3=mp.Vector3(1, 1, -1))
# Corners of the irreducible Brillouin zone for the "I" lattice,
# in order that matches Maldovan2002 Fig 10
vlist = [
mp.Vector3(0, 0, 0.5), # N
mp.Vector3(0.25, 0.25, 0.25), # P
mp.Vector3(0, 0, 0), # Gamma
mp.Vector3(0, 0, 0.5), # N
mp.Vector3(0.5, -0.5, 0.5), # H
mp.Vector3(0.25, 0.25, 0.25) # P
]
k_points = mp.interpolate(4, vlist)
# define a couple of parameters (which we can set from the command_line)
#eps = 20.00 # the dielectric constant of the spheres
#r = 0.25 # the radius of the spheres
dFolder = '/Users/mvchalupnik/Desktop/mympbplots/'
dLoc = dFolder + paramstring
if not os.path.exists(dFolder):
os.makedirs(dFolder)
w = w_actual/a_actual
a = 1
hx = hx_actual/a_actual
hy = hy_actual/a_actual
h = w/2/np.tan(theta*np.pi/180)
####################################################################
#sets size of lattice to be 3D; 1by1by1
geometry_lattice = mp.Lattice(size=mp.Vector3(a, w*3, h*3))
#https://meep.readthedocs.io/en/latest/Python_User_Interface/#prism
beam = mp.Prism([mp.Vector3(0,-w/2, h/2), mp.Vector3(0,w/2, h/2), mp.Vector3(0,0, -h/2)], a, axis=mp.Vector3(1,0,0),
center=None, material=mp.Medium(epsilon=n**2))
#Diamond: n = 2.4063; n^2 = ep_r
hole = mp.Ellipsoid(size=[hx, hy, mp.inf], material=mp.Medium(epsilon=1))
geometry = [beam, hole]
#Symmetry points
k_points = [
mp.Vector3(0,0,0), # Gamma
mp.Vector3(0.5,0,0), # X (normalized to a?)
import math
import meep as mp
from meep import mpb
# A line_defect waveguide in a 2d triangular lattice of dielectric
# rods (c.f. tri_rods.ctl), formed by a row of missing rods along the
# "x" direction. (Here, "x" and "y" refer to the first and second
# basis directions.) This structure supports a single guided band
# within the band gap, much like the analogous waveguide in a square
# lattice of rods (see "Photonic Crystals" by Joannopoulos et al.).
supercell_y = 7 # the (odd) number of lateral supercell periods
geometry_lattice = mp.Lattice(size=mp.Vector3(1, supercell_y),
basis1=mp.Vector3(math.sqrt(3) / 2, 0.5),
basis2=mp.Vector3(math.sqrt(3) / 2, -0.5))
eps = 12 # the dielectric constant of the rods
r = 0.2 # the rod radius in the bulk crystal
geometry = [mp.Cylinder(r, material=mp.Medium(epsilon=eps))]
# duplicate the bulk crystal rods over the supercell:
geometry = mp.geometric_objects_lattice_duplicates(geometry_lattice, geometry)
# add a rod of air, to erase a row of rods and form a waveguide:
geometry += [mp.Cylinder(r, material=mp.air)]
Gamma = mp.Vector3()
K_prime = mp.lattice_to_reciprocal(mp.Vector3(0.5),
def get_mode_solver_coupler(
wg_width: float = 0.5,
gap: float = 0.2,
wg_widths: Optional[Floats] = None,
gaps: Optional[Floats] = None,
wg_thickness: float = 0.22,
slab_thickness: float = 0.0,
ncore: float = 3.47,
nclad: float = 1.44,
nslab: Optional[float] = None,
ymargin: float = 2.0,
sz: float = 2.0,
resolution: int = 32,
nmodes: int = 4,
sidewall_angles: Union[Tuple[float, ...], float] = None,
# sidewall_taper: int = 1,
) -> mpb.ModeSolver:
"""Returns a mode_solver simulation.
Args:
wg_width: wg_width (um)
gap:
wg_widths: list or tuple of waveguide widths.
gaps: list or tuple of waveguide gaps.
wg_thickness: wg height (um)
slab_thickness: thickness for the waveguide slab
ncore: core material refractive index
nclad: clad material refractive index
nslab: Optional slab material refractive index. Defaults to ncore.
ymargin: margin in y.
sz: simulation region thickness (um)
resolution: resolution (pixels/um)
nmodes: number of modes
sidewall_angles: waveguide sidewall angle (radians),
tapers from wg_width at top of slab, upwards, to top of waveguide
::
_____________________________________________________
|
|
| widths[0] widths[1]
| <----------> gaps[0] <---------->
| ___________ <-------------> ___________ _
| | | | | |
sz|_____| |_______________| |_____|
| | wg_thickness
|slab_thickness |
|___________________________________________________|
|
|<---> <--->
|ymargin ymargin
|____________________________________________________
<--------------------------------------------------->
sy
"""
wg_widths = wg_widths or (wg_width, wg_width)
gaps = gaps or (gap, )
material_core = mp.Medium(index=ncore)
material_clad = mp.Medium(index=nclad)
material_slab = mp.Medium(index=nslab or ncore)
# Define the computational cell. We'll make x the propagation direction.
# the other cell sizes should be big enough so that the boundaries are
# far away from the mode field.
sy = np.sum(wg_widths) + np.sum(gaps) + 2 * ymargin
geometry_lattice = mp.Lattice(size=mp.Vector3(0, sy, sz))
geometry = []
y = -sy / 2 + ymargin
gaps = list(gaps) + [0]
for i, wg_width in enumerate(wg_widths):
if sidewall_angles:
geometry.append(
mp.Prism(
vertices=[
mp.Vector3(y=y, z=slab_thickness),
mp.Vector3(y=y + wg_width, z=slab_thickness),
mp.Vector3(x=1, y=y + wg_width, z=slab_thickness),
mp.Vector3(x=1, y=y, z=slab_thickness),
],
height=wg_thickness - slab_thickness,
center=mp.Vector3(
y=y + wg_width / 2,
z=slab_thickness + (wg_thickness - slab_thickness) / 2,
),
# If only 1 angle is specified, use it for all waveguides
sidewall_angle=sidewall_angles if len(
np.unique(sidewall_angles)) == 1 else
sidewall_angles[i],
# axis=mp.Vector3(z=sidewall_taper),
material=material_core,
))
else:
geometry.append(
mp.Block(
size=mp.Vector3(mp.inf, wg_width, wg_thickness),
material=material_core,
center=mp.Vector3(y=y + wg_width / 2, z=wg_thickness / 2),
))
y += gaps[i] + wg_width
# define the 2D blocks for the strip and substrate
geometry += [
mp.Block(
size=mp.Vector3(mp.inf, mp.inf, slab_thickness),
material=material_slab,
center=mp.Vector3(z=slab_thickness / 2),
),
]
# The k (i.e. beta, i.e. propagation constant) points to look at, in
# units of 2*pi/um. We'll look at num_k points from k_min to k_max.
num_k = 9
k_min = 0.1
k_max = 3.0
k_points = mp.interpolate(num_k, [mp.Vector3(k_min), mp.Vector3(k_max)])
# Increase this to see more modes. (The guided ones are the ones below the
# light line, i.e. those with frequencies < kmag / 1.45, where kmag
# is the corresponding column in the output if you grep for "freqs:".)
# use this prefix for output files
wg_widths_str = "_".join([str(i) for i in wg_widths])
gaps_str = "_".join([str(i) for i in gaps])
filename_prefix = (
tmp /
f"coupler_{wg_widths_str}_{gaps_str}_{wg_thickness}_{slab_thickness}")
mode_solver = mpb.ModeSolver(
geometry_lattice=geometry_lattice,
geometry=geometry,
k_points=k_points,
resolution=resolution,
num_bands=nmodes,
filename_prefix=str(filename_prefix),
default_material=material_clad,
)
mode_solver.nmodes = nmodes
mode_solver.info = dict(
wg_widths=wg_widths,
gaps=gaps,
wg_thickness=wg_thickness,
slab_thickness=slab_thickness,
ncore=ncore,
nclad=nclad,
sy=sy,
sz=sz,
resolution=resolution,
nmodes=nmodes,
)
return mode_solver