import copy
from .structure_base import *
import opticalmaterialspy as mat
[docs]class RidgeWaveguide(Slabs):
'''
A general ridge waveguide structure.
Args:
wavelength (float): Wavelength the structure should
operate at.
x_step (float): The grid step in x that the structure
is created on.
y_step (float): The grid step in y that the structure
is created on.
wg_height (float): The height of the ridge.
wg_width (float): The width of the ridge.
sub_height (float): The thickness of the substrate.
sub_width (float): The width of the substrate.
clad_height (float): The thickness of the cladding.
n_sub (float, function): Refractive index of the
substrate. Either a constant (`float`), or
a function that accepts one parameters, the
wavelength, and returns a float of the refractive
index. This is useful when doing wavelength
sweeps and solving for the group velocity. The
function provided could be a Sellmeier equation.
n_wg (float, function): Refractive index of the
waveguide. Either a constant (`float`), or
a function that accepts one parameters, the
wavelength, and returns a float of the refractive
index. This is useful when doing wavelength
sweeps and solving for the group velocity. The
function provided could be a Sellmeier equation.
angle (float): The angle of the sidewall [degrees] of
the waveguide. Default is 0 degrees (vertical
sidewalls).
n_clad (float, function): Refractive index of the
cladding. Either a constant (`float`), or
a function that accepts one parameters, the
wavelength, and returns a float of the refractive
index. This is useful when doing wavelength
sweeps and solving for the group velocity. The
function provided could be a Sellmeier equation.
Default is air.
film_thickness (float, str): The thickness of the
film the waveguide is on. If the waveguide
is a true ridge (fully etched), then the film thickness
can be set to 'wg_height', otherwise the waveguide
is a rib waveguide, and a float should be given
specifying the thickness of the film.
'''
def __init__(self, wavelength, x_step, y_step, wg_height, wg_width, sub_height, sub_width,
clad_height, n_sub, n_wg, angle=0, n_clad=mat.Air().n(),
film_thickness='wg_height'):
Slabs.__init__(self, wavelength, y_step, x_step, sub_width)
self.n_sub = n_sub
self.n_clad = n_clad
self.n_wg = n_wg
self.add_slab(sub_height, n_sub)
if film_thickness != 'wg_height' and film_thickness != wg_height:
assert film_thickness > 0.
self.add_slab(film_thickness-wg_height, n_wg)
k = self.add_slab(wg_height, n_clad)
self.slabs[k].add_material(self.x_ctr-wg_width/2., self.x_ctr+wg_width/2.,
n_wg, angle)
self.add_slab(clad_height, n_clad)
[docs]class WgArray(Slabs):
def __init__(self, wavelength, x_step, y_step, wg_height, wg_widths, wg_gaps, sub_height,
sub_width, clad_height, n_sub, n_wg, angle=0, n_clad=mat.Air().n()):
Slabs.__init__(self, wavelength, y_step, x_step, sub_width)
try:
iter(wg_gaps)
except TypeError:
wg_gaps = [wg_gaps]
try:
assert len(wg_widths) == len(wg_gaps)+1
except TypeError:
wg_widths = [wg_widths for _ in wg_gaps]
wg_gaps_pad = copy.copy(wg_gaps)
wg_gaps_pad.append(0.)
self.add_slab(sub_height, n_sub)
k = self.add_slab(wg_height, n_clad)
air_width_l_r = 0.5*(sub_width - np.sum(wg_widths) - np.sum(wg_gaps))
position = air_width_l_r
for wg_width, wg_gap in zip(wg_widths, wg_gaps_pad):
self.slabs[k].add_material(position, position + wg_width, n_wg, angle)
position += wg_width + wg_gap
self.add_slab(clad_height, n_clad)