# This code is part of KQCircuits
# Copyright (C) 2021 IQM Finland Oy
#
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
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# version.
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# (meetiqm.com/developers/osstmpolicy). IQM welcomes contributions to the code. Please see our contribution agreements
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import math
from kqcircuits.util.parameters import Param, pdt
from kqcircuits.qubits.qubit import Qubit
from kqcircuits.pya_resolver import pya
from kqcircuits.util.refpoints import JunctionSimPort
[docs]
class Swissmon(Qubit):
"""The PCell declaration for a Swissmon qubit.
Swissmon type qubit. Each arm (West, North, East, South) has it's own arm gap width
(``gap_width``) and arm metal width (``arm_width``). SQUID is loaded from another library.
Option of having fluxline. Refpoints for 3 couplers, fluxline position and chargeline position.
Length between the ports is from waveguide port to the rectangular part of the launcher pad.
Length of the fingers is also used for the length of the launcher pad.
.. MARKERS_FOR_PNG 56,-61 140,0 0,175 -64,117
"""
arm_length = Param(pdt.TypeList, "Arm length (um, WNES))", [300.0 / 2] * 4)
arm_width = Param(pdt.TypeList, "Arm metal width (um, WNES)", [24, 24, 24, 24])
gap_width = Param(pdt.TypeList, "Arm gap width (um, WNES)", [12, 12, 12, 12])
cpl_width = Param(pdt.TypeList, "Coupler width (um, WNE)", [24, 24, 24])
cpl_length = Param(pdt.TypeList, "Coupler lengths (um, WNE)", [120, 120, 120])
cpl_gap = Param(pdt.TypeList, "Coupler gap (um, WNE)", [102, 102, 102])
port_width = Param(pdt.TypeList, "Port width (um, WNE)", [10, 10, 10])
cl_offset = Param(pdt.TypeList, "Chargeline offset (um, um)", [200, 200])
island_r = Param(pdt.TypeDouble, "Center island rounding radius", 5, unit="μm")
[docs]
def build(self):
self._produce_cross_and_squid()
self._produce_chargeline() # refpoint only ATM
self.produce_fluxline()
for i in range(3):
self._produce_coupler(i)
def _produce_chargeline(self):
# shorthands
l = [float(offset) for offset in self.cl_offset] # swissmon arm length from the center of the cross (refpoint)
# add ref point
# port_ref = pya.DPoint(-g-b-a/2, -l)
port_ref = pya.DPoint(-l[0], -l[1])
self.add_port("drive", port_ref)
def _produce_coupler(self, cpl_nr):
# shorthand
a = float(self.port_width[cpl_nr])
b = self.b
[ww, wn, we, ws] = [float(width) / 2 for width in self.arm_width]
aw = [ww, wn, we, ws][cpl_nr]
w = float(self.cpl_width[cpl_nr])
l = float(self.cpl_length[cpl_nr])
g = float(self.cpl_gap[cpl_nr]) / 2
# Location for connecting the waveguides to
port_shape = pya.DBox(-a / 2, 0, a / 2, b)
port_region = pya.Region(port_shape.to_itype(self.layout.dbu))
if l > 0:
# Horseshoe opened to below
# Refpoint in the top center
shoe_points = [
pya.DPoint(a, 0),
pya.DPoint(g + w, 0),
pya.DPoint(g + w, -l),
pya.DPoint(g, -l),
pya.DPoint(g, -w),
pya.DPoint(-g, -w),
pya.DPoint(-g, -l),
pya.DPoint(-g - w, -l),
pya.DPoint(-g - w, 0),
pya.DPoint(-a, 0),
]
shoe = pya.DPolygon(shoe_points)
shoe.size(b)
shoe.insert_hole(shoe_points[::-1])
# convert to range and recover CPW port
shoe_region = pya.Region(shoe.to_itype(self.layout.dbu))
shoe_region.round_corners(self.island_r / self.layout.dbu, self.island_r / self.layout.dbu, self.n)
shoe_region2 = shoe_region - port_region
# move to the north arm of swiss cross
ground_width = (2 * g - float(self.gap_width[1]) - 2 * b) / 2
shift_up = float(self.arm_length[cpl_nr]) + (float(self.gap_width[1]) - 2 * aw) / 2 + ground_width + w + b
transf = pya.DCplxTrans(1, 0, False, pya.DVector(0, shift_up))
# rotate to the correct direction
rotation = [pya.DCplxTrans.R90, pya.DCplxTrans.R0, pya.DCplxTrans.R270][cpl_nr]
# draw
if l > 0:
self.cell.shapes(self.get_layer("base_metal_gap_wo_grid")).insert(
shoe_region2.transformed((rotation * transf).to_itrans(self.layout.dbu))
)
self.cell.shapes(self.get_layer("waveguide_path")).insert(
port_region.transformed((rotation * transf).to_itrans(self.layout.dbu))
)
# protection
if l > 0:
protection = pya.DBox(
-g - w - b - self.margin, -l - b - self.margin, g + w + b + self.margin, b + self.margin
)
self.add_protection(protection.transformed((rotation * transf)))
# add ref point
port_ref = pya.DPoint(0, b)
self.add_port("cplr{}".format(cpl_nr), (rotation * transf).trans(port_ref), rotation * pya.DVector(0, 1))
def _produce_cross_and_squid(self):
"""Produces the cross and squid for the Swissmon."""
# shorthand
[ww, wn, we, ws] = [float(width) / 2 for width in self.arm_width]
l = [float(length) for length in self.arm_length]
[sw, sn, se, ss] = [float(width) for width in self.gap_width]
# # SQUID
# SQUID origin at the ground plane edge
squid_transf = pya.DCplxTrans(1, 0, False, pya.DVector(0, -l[3] - ss))
squid_ref_rel = self.produce_squid(squid_transf)
# SQUID port_common at the end of the south arm
squid_length = squid_ref_rel["port_common"].distance(pya.DPoint(0, 0))
# Swissmon etch region
# refpoint in the center of the swiss cross
cross_island_points = [
pya.DPoint(wn, we),
pya.DPoint(l[2], we),
pya.DPoint(l[2], -we),
pya.DPoint(ws, -we),
pya.DPoint(ws, -l[3] - ss + squid_length),
pya.DPoint(-ws, -l[3] - ss + squid_length),
pya.DPoint(-ws, -ww),
pya.DPoint(-l[0], -ww),
pya.DPoint(-l[0], ww),
pya.DPoint(-wn, ww),
pya.DPoint(-wn, l[1]),
pya.DPoint(wn, l[1]),
]
# refpoint in the center of the swiss cross
cross_gap_points = [
pya.DPoint(wn + sn, we + se),
pya.DPoint(l[2] + se, we + se),
pya.DPoint(l[2] + se, -we - se),
pya.DPoint(ws + ss, -we - se),
pya.DPoint(ws + ss, -l[3] - ss),
pya.DPoint(-ws - ss, -l[3] - ss),
pya.DPoint(-ws - ss, -ww - sw),
pya.DPoint(-l[0] - sw, -ww - sw),
pya.DPoint(-l[0] - sw, ww + sw),
pya.DPoint(-wn - sn, ww + sw),
pya.DPoint(-wn - sn, l[1] + sn),
pya.DPoint(wn + sn, l[1] + sn),
]
cross = pya.DPolygon(cross_gap_points)
cross.insert_hole(cross_island_points)
cross_rounded = cross.round_corners(self.island_r, self.island_r, self.n)
region_etch = pya.Region([cross_rounded.to_itype(self.layout.dbu)])
self.cell.shapes(self.get_layer("base_metal_gap_wo_grid")).insert(region_etch)
# Protection
cross_protection = pya.DPolygon(
[
p
+ pya.DVector(
math.copysign(max([sw, sn, se, ss]) + self.margin, p.x),
math.copysign(max([sw, sn, se, ss]) + self.margin, p.y),
)
for p in cross_gap_points
]
)
self.add_protection(cross_protection)
# Probepoint
probepoint = pya.DPoint(0, 0)
self.refpoints["probe_qb_c"] = probepoint
[docs]
@classmethod
def get_sim_ports(cls, simulation): # pylint: disable=unused-argument
return [JunctionSimPort()]