from __future__ import annotations
from numpy import ndarray
import gdsfactory as gf
from gdsfactory.component import Component
from gdsfactory.components.bezier import bezier
from gdsfactory.components.coupler_straight_asymmetric import (
coupler_straight_asymmetric,
)
from gdsfactory.components.taper import taper
from gdsfactory.snap import snap_to_grid2x
from gdsfactory.typings import CrossSectionSpec, Float2, Float3
[docs]
@gf.cell
def polarization_splitter_rotator(
width_taper_in: Float3 = (0.54, 0.69, 0.83),
length_taper_in: Float2 | Float3 = (4.0, 44.0),
width_coupler: Float2 = (0.9, 0.405),
length_coupler: float = 7.0,
gap: float = 0.15,
width_out: float = 0.54,
length_out: float = 14.33,
dy: float = 5.0,
cross_section: CrossSectionSpec = "xs_sc",
) -> Component:
"""Returns polarization splitter rotator
"Novel concept for ultracompact polarization splitter-rotator
based on silicon nanowires." By D. Dai, and J. E. Bowers
(Optics express vol 19, no. 11 pp. 10940-10949 (2011)).
Args:
width_taper_in: Three west widths of the input tapers in um.
length_taper_in: Two or three length of the bend regions in um.
width_coupler: Top and bottom widths of the coupling region in um.
length_coupler: Length of the coupling region in um.
gap: Distance between the coupler in um.
width_out: Width of the splitter region in um.
length_out: Length of the splitter region in um.
dy: Port-to-port distance between the splitter region in um.
cross_section: cross-section spec.
Notes:
The length of third input taper is automatically determined
if only two lengths are in arguments.
"""
c = gf.Component()
x = gf.get_cross_section(cross_section=cross_section)
w0, w1, w2 = width_taper_in
w3, w4 = width_coupler
if len(length_taper_in) == 2:
l1, l2 = length_taper_in
l3 = l1 * (w3 - w2) / (w1 - w0)
else:
l1, l2, l3 = length_taper_in
taper_in1 = c << taper(length=l1, width1=w0, width2=w1, cross_section=x)
taper_in2 = c << taper(length=l2, width1=w1, width2=w2, cross_section=x)
taper_in3 = c << taper(length=l3, width1=w2, width2=w3, cross_section=x)
coupler = c << coupler_straight_asymmetric(
length=length_coupler, gap=gap, width_top=w4, width_bot=w3, cross_section=x
)
def bend_s_width(t: ndarray) -> ndarray:
return snap_to_grid2x(w4 + (width_out - w4) * t)
x_bend = x.copy(width_function=bend_s_width)
bend_s_var = c << bezier(
control_points=(
(0, 0),
(length_out / 2, 0),
(length_out / 2, dy),
(length_out, dy),
),
cross_section=x_bend,
)
taper_out = c << taper(
length=length_out, width1=w3, width2=width_out, cross_section=x
)
taper_in3.connect("o2", destination=coupler.ports["o1"])
taper_in2.connect("o2", destination=taper_in3.ports["o1"])
taper_in1.connect("o2", destination=taper_in2.ports["o1"])
taper_out.connect("o1", destination=coupler.ports["o4"])
bend_s_var.connect("o1", destination=coupler.ports["o3"])
c.add_port("o1", port=taper_in1.ports["o1"])
c.add_port("o2", port=bend_s_var.ports["o2"])
c.add_port("o3", port=taper_out.ports["o2"])
c.absorb(coupler)
c.absorb(taper_in3)
c.absorb(taper_in2)
c.absorb(taper_in1)
c.absorb(taper_out)
c.absorb(bend_s_var)
c.info["length"] = bend_s_var.info["length"]
c.info["min_bend_radius"] = bend_s_var.info["min_bend_radius"]
c.auto_rename_ports()
return c
if __name__ == "__main__":
c = polarization_splitter_rotator(length_taper_in=(10, 69))
c.show(show_ports=True)
