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start work on tutorial

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jan 2021-05-16 19:04:31 -07:00
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examples/tutorial/README.md Normal file
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examples/tutorial/basic.py Normal file
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from typing import Tuple, Sequence
import numpy # type: ignore
from numpy import pi
from masque import layer_t, Pattern, SubPattern, Label
from masque.shapes import Circle, Arc
from masque.builder import Device, Port
from masque.library import Library, DeviceLibrary
import masque.file.gdsii
import pcgen
def hole(radius: float,
layer: layer_t = (1, 0),
) -> Pattern:
"""
Generate a pattern containing a single circular hole.
Args:
layer: Layer to draw the circle on.
radius: Circle radius.
Returns:
Pattern, named `'hole'`
"""
pat = Pattern('hole', shapes=[
Circle(radius=radius, offset=(0, 0), layer=layer)
])
return pat
def smile(radius: float,
layer: layer_t = (1, 0),
secondary_layer: layer_t = (1, 2)
) -> Pattern:
"""
Generate a pattern containing a single smiley face.
Args:
radius: Boundary circle radius.
layer: Layer to draw the outer circle on.
secondary_layer: Layer to draw eyes and smile on.
Returns:
Pattern, named `'smile'`
"""
# Make an empty pattern
pat = Pattern('smile')
# Add all the shapes we want
pat.shapes += [
Circle(radius=radius, offset=(0, 0), layer=layer), # Outer circle
Circle(radius=radius / 10, offset=(radius / 3, radius / 3), layer=secondary_layer),
Circle(radius=radius / 10, offset=(-radius / 3, radius / 3), layer=secondary_layer),
Arc(radii=(radius * 2 / 3, radius * 2 / 3), # Underlying ellipse radii
angles=(7 / 6 * pi, 11 / 6 * pi), # Angles limiting the arc
width=radius / 10,
offset=(0, 0),
layer=secondary_layer),
]
return pat
def _main() -> None:
hole_pat = hole(1000)
smile_pat = smile(1000)
masque.file.gdsii.writefile([hole_pat, smile_pat], 'basic.gds', 1e-9, 1e-3)
smile_pat.visualize()
if __name__ == '__main__':
_main()

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"""
Routines for creating normalized 2D lattices and common photonic crystal
cavity designs.
"""
from typing import Sequence, Tuple
import numpy # type: ignore
def triangular_lattice(dims: Tuple[int, int],
asymmetric: bool = False,
origin: str = 'center',
) -> numpy.ndarray:
"""
Return an ndarray of `[[x0, y0], [x1, y1], ...]` denoting lattice sites for
a triangular lattice in 2D.
Args:
dims: Number of lattice sites in the [x, y] directions.
asymmetric: If true, each row will contain the same number of
x-coord lattice sites. If false, every other row will be
one site shorter (to make the structure symmetric).
origin: If 'corner', the least-(x,y) lattice site is placed at (0, 0)
If 'center', the center of the lattice (not necessarily a
lattice site) is placed at (0, 0).
Returns:
`[[x0, y0], [x1, 1], ...]` denoting lattice sites.
"""
sx, sy = numpy.meshgrid(numpy.arange(dims[0], dtype=float),
numpy.arange(dims[1], dtype=float), indexing='ij')
sx[sy % 2 == 1] += 0.5
sy *= numpy.sqrt(3) / 2
if not asymmetric:
which = sx != sx.max()
sx = sx[which]
sy = sy[which]
xy = numpy.column_stack((sx.flat, sy.flat))
if origin == 'center':
xy -= (xy.max(axis=0) - xy.min(axis=0)) / 2
elif origin == 'corner':
pass
else:
raise Exception(f'Invalid value for `origin`: {origin}')
return xy[xy[:, 0].argsort(), :]
def square_lattice(dims: Tuple[int, int]) -> numpy.ndarray:
"""
Return an ndarray of `[[x0, y0], [x1, y1], ...]` denoting lattice sites for
a square lattice in 2D. The lattice will be centered around (0, 0).
Args:
dims: Number of lattice sites in the [x, y] directions.
Returns:
`[[x0, y0], [x1, 1], ...]` denoting lattice sites.
"""
xs, ys = numpy.meshgrid(range(dims[0]), range(dims[1]), 'xy')
xs -= dims[0]/2
ys -= dims[1]/2
xy = numpy.vstack((xs.flatten(), ys.flatten())).T
return xy[xy[:, 0].argsort(), ]
# ### Photonic crystal functions ###
def nanobeam_holes(a_defect: float,
num_defect_holes: int,
num_mirror_holes: int
) -> numpy.ndarray:
"""
Returns a list of `[[x0, r0], [x1, r1], ...]` of nanobeam hole positions and radii.
Creates a region in which the lattice constant and radius are progressively
(linearly) altered over num_defect_holes holes until they reach the value
specified by a_defect, then symmetrically returned to a lattice constant and
radius of 1, which is repeated num_mirror_holes times on each side.
Args:
a_defect: Minimum lattice constant for the defect, as a fraction of the
mirror lattice constant (ie., for no defect, a_defect = 1).
num_defect_holes: How many holes form the defect (per-side)
num_mirror_holes: How many holes form the mirror (per-side)
Returns:
Ndarray `[[x0, r0], [x1, r1], ...]` of nanobeam hole positions and radii.
"""
a_values = numpy.linspace(a_defect, 1, num_defect_holes, endpoint=False)
xs = a_values.cumsum() - (a_values[0] / 2) # Later mirroring makes center distance 2x as long
mirror_xs = numpy.arange(1, num_mirror_holes + 1, dtype=float) + xs[-1]
mirror_rs = numpy.ones_like(mirror_xs)
return numpy.vstack((numpy.hstack((-mirror_xs[::-1], -xs[::-1], xs, mirror_xs)),
numpy.hstack((mirror_rs[::-1], a_values[::-1], a_values, mirror_rs)))).T
def waveguide(length: int, num_mirror: int) -> numpy.ndarray:
"""
Line defect waveguide in a triangular lattice.
Args:
length: waveguide length (number of holes in x direction)
num_mirror: Mirror length (number of holes per side; total size is
`2 * n + 1` holes.
Returns:
`[[x0, y0], [x1, y1], ...]` for all the holes
"""
p = triangular_lattice([length + 2, 2 * num_mirror + 1])
p = p[p[:, 1] != 0, :]
p = p[numpy.abs(p[:, 0]) <= length / 2]
return p
def wgbend(num_mirror: int) -> numpy.ndarray:
"""
Line defect waveguide bend in a triangular lattice.
Args:
num_mirror: Mirror length (number of holes per side; total size is
approximately `2 * n + 1`
Returns:
`[[x0, y0], [x1, y1], ...]` for all the holes
"""
p = triangular_lattice([4 * num_mirror + 1, 4 * num_mirror + 1])
left_horiz = (p[:, 1] == 0) & (p[:, 0] <= 0)
p = p[~left_horiz, :]
right_diag = numpy.isclose(p[:, 1], p[:, 0] * numpy.sqrt(3)) & (p[:, 0] >= 0)
p = p[~right_diag, :]
edge_left = p[:, 0] < -num_mirror
edge_bot = p[:, 1] < -num_mirror
p = p[~edge_left & ~edge_bot, :]
edge_diag_up = p[:, 0] * numpy.sqrt(3) > p[:, 1] + 2 * num_mirror + 0.1
edge_diag_dn = p[:, 0] / numpy.sqrt(3) > -p[:, 1] + num_mirror + 1.1
p = p[~edge_diag_up & ~edge_diag_dn, :]
return p
def y_splitter(num_mirror: int) -> numpy.ndarray:
"""
Line defect waveguide y-splitter in a triangular lattice.
Args:
num_mirror: Mirror length (number of holes per side; total size is
approximately `2 * n + 1` holes.
Returns:
`[[x0, y0], [x1, y1], ...]` for all the holes
"""
p = triangular_lattice([4 * num_mirror + 1, 4 * num_mirror + 1])
left_horiz = (p[:, 1] == 0) & (p[:, 0] <= 0)
p = p[~left_horiz, :]
# y = +-sqrt(3) * x
right_diag_up = numpy.isclose(p[:, 1], p[:, 0] * numpy.sqrt(3)) & (p[:, 0] >= 0)
right_diag_dn = numpy.isclose(p[:, 1], -p[:, 0] * numpy.sqrt(3)) & (p[:, 0] >= 0)
p = p[~right_diag_up & ~right_diag_dn, :]
edge_left = p[:, 0] < -num_mirror
p = p[~edge_left, :]
edge_diag_up = p[:, 0] / numpy.sqrt(3) > p[:, 1] + num_mirror + 1.1
edge_diag_dn = p[:, 0] / numpy.sqrt(3) > -p[:, 1] + num_mirror + 1.1
p = p[~edge_diag_up & ~edge_diag_dn, :]
return p
def ln_defect(mirror_dims: Tuple[int, int],
defect_length: int,
) -> numpy.ndarray:
"""
N-hole defect in a triangular lattice.
Args:
mirror_dims: [x, y] mirror lengths (number of holes). Total number of holes
is 2 * n + 1 in each direction.
defect_length: Length of defect. Should be an odd number.
Returns:
`[[x0, y0], [x1, y1], ...]` for all the holes
"""
if defect_length % 2 != 1:
raise Exception('defect_length must be odd!')
p = triangular_lattice([2 * d + 1 for d in mirror_dims])
half_length = numpy.floor(defect_length / 2)
hole_nums = numpy.arange(-half_length, half_length + 1)
holes_to_keep = numpy.in1d(p[:, 0], hole_nums, invert=True)
return p[numpy.logical_or(holes_to_keep, p[:, 1] != 0), ]
def ln_shift_defect(mirror_dims: Tuple[int, int],
defect_length: int,
shifts_a: Sequence[float] = (0.15, 0, 0.075),
shifts_r: Sequence[float] = (1, 1, 1)
) -> numpy.ndarray:
"""
N-hole defect with shifted holes (intended to give the mode a gaussian profile
in real- and k-space so as to improve both Q and confinement). Holes along the
defect line are shifted and altered according to the shifts_* parameters.
Args:
mirror_dims: [x, y] mirror lengths (number of holes). Total number of holes
is `2 * n + 1` in each direction.
defect_length: Length of defect. Should be an odd number.
shifts_a: Percentage of a to shift (1st, 2nd, 3rd,...) holes along the defect line
shifts_r: Factor to multiply the radius by. Should match length of shifts_a
Returns:
`[[x0, y0, r0], [x1, y1, r1], ...]` for all the holes
"""
if not hasattr(shifts_a, "__len__") and shifts_a is not None:
shifts_a = [shifts_a]
if not hasattr(shifts_r, "__len__") and shifts_r is not None:
shifts_r = [shifts_r]
xy = ln_defect(mirror_dims, defect_length)
# Add column for radius
xyr = numpy.hstack((xy, numpy.ones((xy.shape[0], 1))))
# Shift holes
# Expand shifts as necessary
n_shifted = max(len(shifts_a), len(shifts_r))
tmp_a = numpy.array(shifts_a)
shifts_a = numpy.ones((n_shifted, ))
shifts_a[:len(tmp_a)] = tmp_a
tmp_r = numpy.array(shifts_r)
shifts_r = numpy.ones((n_shifted, ))
shifts_r[:len(tmp_r)] = tmp_r
x_removed = numpy.floor(defect_length / 2)
for ind in range(n_shifted):
for sign in (-1, 1):
x_val = sign * (x_removed + ind + 1)
which = numpy.logical_and(xyr[:, 0] == x_val, xyr[:, 1] == 0)
xyr[which, ] = (x_val + numpy.sign(x_val) * shifts_a[ind], 0, shifts_r[ind])
return xyr
def r6_defect(mirror_dims: Tuple[int, int]) -> numpy.ndarray:
"""
R6 defect in a triangular lattice.
Args:
mirror_dims: [x, y] mirror lengths (number of holes). Total number of holes
is 2 * n + 1 in each direction.
Returns:
`[[x0, y0], [x1, y1], ...]` specifying hole centers.
"""
xy = triangular_lattice([2 * d + 1 for d in mirror_dims])
rem_holes_plus = numpy.array([[1, 0],
[0.5, +numpy.sqrt(3)/2],
[0.5, -numpy.sqrt(3)/2]])
rem_holes = numpy.vstack((rem_holes_plus, -rem_holes_plus))
for rem_xy in rem_holes:
xy = xy[(xy != rem_xy).any(axis=1), ]
return xy
def l3_shift_perturbed_defect(
mirror_dims: Tuple[int, int],
perturbed_radius: float = 1.1,
shifts_a: Sequence[float] = (),
shifts_r: Sequence[float] = ()
) -> numpy.ndarray:
"""
3-hole defect with perturbed hole sizes intended to form an upwards-directed
beam. Can also include shifted holes along the defect line, intended
to give the mode a more gaussian profile to improve Q.
Args:
mirror_dims: [x, y] mirror lengths (number of holes). Total number of holes
is 2 * n + 1 in each direction.
perturbed_radius: Amount to perturb the radius of the holes used for beam-forming
shifts_a: Percentage of a to shift (1st, 2nd, 3rd,...) holes along the defect line
shifts_r: Factor to multiply the radius by. Should match length of shifts_a
Returns:
`[[x0, y0, r0], [x1, y1, r1], ...]` for all the holes
"""
xyr = ln_shift_defect(mirror_dims, 3, shifts_a, shifts_r)
abs_x, abs_y = (numpy.fabs(xyr[:, i]) for i in (0, 1))
# Sorted unique xs and ys
# Ignore row y=0 because it might have shifted holes
xs = numpy.unique(abs_x[abs_x != 0])
ys = numpy.unique(abs_y)
# which holes should be perturbed? (xs[[3, 7]], ys[1]) and (xs[[2, 6]], ys[2])
perturbed_holes = ((xs[a], ys[b]) for a, b in ((3, 1), (7, 1), (2, 2), (6, 2)))
for row in xyr:
if numpy.fabs(row) in perturbed_holes:
row[2] = perturbed_radius
return xyr

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from typing import Tuple, Sequence
import numpy # type: ignore
from numpy import pi
from masque import layer_t, Pattern, SubPattern, Label
from masque.shapes import Polygon, Circle
from masque.builder import Device, Port
from masque.library import Library, DeviceLibrary
from masque.file.gdsii import writefile
import pcgen
import basic
def perturbed_l3(lattice_constant: float,
hole: Pattern,
trench_dose: float = 1.0,
trench_layer: layer_t = (1, 0),
shifts_a: Sequence[float] = (0.15, 0, 0.075),
shifts_r: Sequence[float] = (1.0, 1.0, 1.0),
xy_size: Tuple[int, int] = (10, 10),
perturbed_radius: float = 1.1,
trench_width: float = 1200,
) -> Device:
"""
Generate a `Device` representing a perturbed L3 cavity.
Args:
lattice_constant: Distance between nearest neighbor holes
hole: `Pattern` object containing a single hole
trench_dose: Dose for the trenches. Default 1.0. (Hole dose is 1.0.)
trench_layer: Layer for the trenches, default `(1, 0)`.
shifts_a: passed to `pcgen.l3_shift`; specifies lattice constant
(1 - multiplicative factor) for shifting holes adjacent to
the defect (same row). Default `(0.15, 0, 0.075)` for first,
second, third holes.
shifts_r: passed to `pcgen.l3_shift`; specifies radius for perturbing
holes adjacent to the defect (same row). Default 1.0 for all holes.
Provided sequence should have same length as `shifts_a`.
xy_size: `(x, y)` number of mirror periods in each direction; total size is
`2 * n + 1` holes in each direction. Default (10, 10).
perturbed_radius: radius of holes perturbed to form an upwards-driected beam
(multiplicative factor). Default 1.1.
trench width: Width of the undercut trenches. Default 1200.
Returns:
`Device` object representing the L3 design.
"""
xyr = pcgen.l3_shift_perturbed_defect(mirror_dims=xy_size,
perturbed_radius=perturbed_radius,
shifts_a=shifts_a,
shifts_r=shifts_r)
pat = Pattern(f'L3p-a{lattice_constant:g}rp{perturbed_radius:g}')
pat.subpatterns += [SubPattern(hole,
offset=(lattice_constant * x,
lattice_constant * y),
scale=r)
for x, y, r in xyr]
min_xy, max_xy = pat.get_bounds()
trench_dx = max_xy[0] - min_xy[0]
pat.shapes += [
Polygon.rect(ymin=max_xy[1], xmin=min_xy[0], lx=trench_dx, ly=trench_width,
layer=trench_layer, dose=trench_dose),
Polygon.rect(ymax=min_xy[1], xmin=min_xy[0], lx=trench_dx, ly=trench_width,
layer=trench_layer, dose=trench_dose),
]
extent = lattice_constant * xy_size[0]
ports = {
'input': Port((-extent, 0), rotation=0, ptype=1),
'output': Port((extent, 0), rotation=pi, ptype=1),
}
return Device(pat, ports)
def waveguide(lattice_constant: float,
hole: Pattern,
length: int,
mirror_periods: int,
) -> Device:
"""
Generate a `Device` representing a photonic crystal line-defect waveguide.
Args:
lattice_constant: Distance between nearest neighbor holes
hole: `Pattern` object containing a single hole
length: Distance (number of mirror periods) between the input and output ports.
Ports are placed at lattice sites.
mirror_periods: Number of hole rows on each side of the line defect
Returns:
`Device` object representing the waveguide.
"""
xy = pcgen.waveguide(length=length, num_mirror=mirror_periods)
pat = Pattern(f'_wg-a{lattice_constant:g}l{length}')
pat.subpatterns += [SubPattern(hole, offset=(lattice_constant * x,
lattice_constant * y))
for x, y in xy]
extent = lattice_constant * length / 2
ports = {
'left': Port((-extent, 0), rotation=0, ptype=1),
'right': Port((extent, 0), rotation=pi, ptype=1),
}
return Device(pat, ports)
def bend(lattice_constant: float,
hole: Pattern,
mirror_periods: int,
) -> Device:
"""
Generate a `Device` representing a 60-degree counterclockwise bend in a photonic crystal
line-defect waveguide.
Args:
lattice_constant: Distance between nearest neighbor holes
hole: `Pattern` object containing a single hole
mirror_periods: Minimum number of mirror periods on each side of the line defect.
Returns:
`Device` object representing the waveguide bend.
Ports are named 'left' (input) and 'right' (output).
"""
xy = pcgen.wgbend(num_mirror=mirror_periods)
pat= Pattern(f'_wgbend-a{lattice_constant:g}l{mirror_periods}')
pat.subpatterns += [SubPattern(hole, offset=(lattice_constant * x,
lattice_constant * y))
for x, y in xy]
extent = lattice_constant * mirror_periods
ports = {
'left': Port((-extent, 0), rotation=0, ptype=1),
'right': Port((extent / 2,
extent * numpy.sqrt(3) / 2), rotation=pi * 4 / 3, ptype=1),
}
return Device(pat, ports)
def y_splitter(lattice_constant: float,
hole: Pattern,
mirror_periods: int,
) -> Device:
"""
Generate a `Device` representing a photonic crystal line-defect waveguide y-splitter.
Args:
lattice_constant: Distance between nearest neighbor holes
hole: `Pattern` object containing a single hole
mirror_periods: Minimum number of mirror periods on each side of the line defect.
Returns:
`Device` object representing the y-splitter.
Ports are named 'in', 'top', and 'bottom'.
"""
xy = pcgen.y_splitter(num_mirror=mirror_periods)
pat = Pattern(f'_wgsplit_half-a{lattice_constant:g}l{mirror_periods}')
pat.subpatterns += [SubPattern(hole, offset=(lattice_constant * x,
lattice_constant * y))
for x, y in xy]
extent = lattice_constant * mirror_periods
ports = {
'in': Port((-extent, 0), rotation=0, ptype=1),
'top': Port((extent / 2,
extent * numpy.sqrt(3) / 2), rotation=pi * 4 / 3, ptype=1),
'bot': Port((extent / 2,
-extent * numpy.sqrt(3) / 2), rotation=pi * 2 / 3, ptype=1),
}
return Device(pat, ports)
def label_ports(device: Device, layer: layer_t = (3, 0)) -> Device:
"""
Place a text label at each port location, specifying the port data.
This can be used to debug port locations or to automatically generate ports
when reading in a GDS file.
Args:
device: The device which is to have its ports labeled.
layer: The layer on which the labels will be placed.
Returns:
`device` is returned (and altered in-place)
"""
for name, port in device.ports.items():
angle_deg = numpy.rad2deg(port.rotation)
device.pattern.labels += [
Label(string=f'{name} (angle {angle_deg:g})', layer=layer, offset=port.offset)
]
return device
def main():
a = 512
radius = a / 2 * 0.75
smile = basic.smile(radius)
hole = basic.hole(radius)
wg10 = label_ports(waveguide(lattice_constant=a, hole=hole, length=10, mirror_periods=5))
wg05 = label_ports(waveguide(lattice_constant=a, hole=hole, length=5, mirror_periods=5))
wg28 = label_ports(waveguide(lattice_constant=a, hole=hole, length=28, mirror_periods=5))
bend0 = label_ports(bend(lattice_constant=a, hole=hole, mirror_periods=5))
l3cav = label_ports(perturbed_l3(lattice_constant=a, hole=smile, xy_size=(4, 10)))
ysplit = label_ports(y_splitter(lattice_constant=a, hole=hole, mirror_periods=5))
dev = Device(name='my_bend', ports={})
dev.place(wg10, offset=(0, 0), port_map={'left': 'in', 'right': 'signal'})
dev.plug(wg10, {'signal': 'left'})
dev.plug(ysplit, {'signal': 'in'}, {'top': 'signal1', 'bot': 'signal2'})
dev.plug(wg05, {'signal1': 'left'})
dev.plug(wg05, {'signal2': 'left'})
dev.plug(bend0, {'signal1': 'right'})
dev.plug(bend0, {'signal2': 'left'})
dev.plug(wg10, {'signal1': 'left'})
dev.plug(l3cav, {'signal1': 'input'})
dev.plug(wg10, {'signal1': 'left'})
dev.plug(wg28, {'signal2': 'left'})
dev.plug(bend0, {'signal1': 'right'})
dev.plug(bend0, {'signal2': 'left'})
dev.plug(wg05, {'signal1': 'left'})
dev.plug(wg05, {'signal2': 'left'})
dev.plug(ysplit, {'signal1': 'bot', 'signal2': 'top'}, {'in': 'signal_out'})
dev.plug(wg10, {'signal_out': 'left'})
writefile(dev.pattern, 'phc.gds', 1e-9, 1e-3)
dev.pattern.visualize()
if __name__ == '__main__':
main()