Source code for kqcircuits.qubits.qubit

# This code is part of KQCircuits
# Copyright (C) 2021 IQM Finland Oy
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import math

from kqcircuits.elements.element import Element
from kqcircuits.elements.fluxlines.fluxline import Fluxline
from kqcircuits.pya_resolver import pya
from kqcircuits.util.parameters import Param, pdt, add_parameters_from
from kqcircuits.junctions.junction import Junction
from kqcircuits.junctions.squid import Squid
from kqcircuits.junctions.sim import Sim

[docs]@add_parameters_from(Fluxline, "fluxline_type", "fluxline_parameters", "_fluxline_parameters") @add_parameters_from( Squid, "junction_width", "loop_area", "junction_type", "junction_parameters", "_junction_parameters" ) @add_parameters_from(Sim, "junction_total_length") class Qubit(Element): """Base class for qubit objects without actual produce function. Collection of shared sub routines for shared parameters and producing shared aspects of qubit geometry including * possible fluxlines * e-beam layers for SQUIDs * SQUID name parameter It is customary to also define probepoints for a qubit. Simply define two refpoints as appropriate probepoints. For single island qubits:: self.refpoints["probe_ground"] = pya.DPoint(...) self.refpoints["probe_island"] = pya.DPoint(...) self.cell.shapes(self.get_layer("ground_grid_avoidance")).insert( pya.DBox(-20.0, -20.0, 20.0, 20.0).moved(self.refpoints["probe_ground"])) For double island qubits:: self.refpoints["probe_island_1"] = pya.DPoint(...) self.refpoints["probe_island_2"] = pya.DPoint(...) """ LIBRARY_NAME = "Qubit Library" LIBRARY_DESCRIPTION = "Library for qubits." LIBRARY_PATH = "qubits" mirror_squid = Param(pdt.TypeBoolean, "Mirror SQUID by its Y axis", False)
[docs] def coerce_parameters_impl(self): self.sync_parameters(Fluxline) self.sync_parameters(Junction)
[docs] def produce_squid(self, transf, only_arms=False, **parameters): """Produces the squid. Creates the squid cell and inserts it with the given transformation as a subcell. Also inserts the squid parts in "base_metal_gap_wo_grid"-layer to "base_metal_gap_for_EBL"-layer. It also returns a ``right_side`` refpoint, calculated from base_metal_gap_wo_grid layer's bounding box to help with arm_length calculation in JunctionTestPads. Args: transf (DCplxTrans): squid transformation parameters: other parameters for the squid only_arms: Boolean argument that allows to choose whether to create the arms and the squid device or only the arms Returns: (dict): Relative refpoints for the squid """ cell = self.add_element(Squid, junction_type=self.junction_type, **parameters) refpoints_rel = self.get_refpoints(cell) mwidth = cell.dbbox_per_layer(self.get_layer("base_metal_gap_wo_grid")).width() if mwidth > 0.0: refpoints_rel["right_side"] = pya.DPoint(mwidth / 2, 0.0) squid_transf = transf * pya.DTrans.M90 if self.mirror_squid else transf if "squid_index" in parameters: s_index = int(parameters.pop("squid_index")) inst, _ = self.insert_cell(cell, squid_transf, inst_name=f"squid_{s_index}") inst.set_property("squid_index", s_index) else: inst, _ = self.insert_cell(cell, squid_transf, inst_name="squid") if only_arms: # add squid metal etch and unetch shapes to qubit and erase instance of squid for layer_name in ["base_metal_gap_wo_grid", "base_metal_addition"]: region = pya.Region(cell.shapes(self.get_layer(layer_name))) region.transform(inst.cplx_trans) self.cell.shapes(self.get_layer(layer_name)).insert(region) self.cell.erase(inst) else: # add parts of qubit to the layer needed for EBL region = pya.Region(cell.shapes(self.get_layer("base_metal_gap_wo_grid"))) region.transform(inst.cplx_trans) self.cell.shapes(self.get_layer("base_metal_gap_for_EBL")).insert(region) return refpoints_rel
[docs] def produce_fluxline(self, rot=0, trans=pya.DVector(), **parameters): """Produces the fluxline. Creates the fluxline cell and inserts it as a subcell. The "flux" and "flux_corner" ports are made available for the qubit. By default, fluxlines align their "origin_fluxline" refpoint to "origin_squid" refpoint in the direction of "port_common". However, the user might tweak the alignment direction by using the argument rot and the relative position by an extra pya.DVector(x, y) allowing to tune the position to achieve the desired design parameters. Args: rot: Extra rotation of the fluxline, in degrees trans (DVector): fluxline x/y translation parameters: parameters for the fluxline to overwrite default and subclass parameters """ if self.fluxline_type == "none": return cell = self.add_element(Fluxline, **parameters) refpoints_so_far = self.get_refpoints(self.cell) squid_edge = refpoints_so_far["origin_squid"] a = squid_edge - refpoints_so_far["port_common"] rotation = math.atan2(a.y, a.x) / math.pi * 180 + 90 total_transformation = pya.DCplxTrans(1, rotation + rot, False, squid_edge - self.refpoints["base"] + trans) cell_inst, _ = self.insert_cell(cell, total_transformation) self.copy_port("flux", cell_inst)