API

analysis

fem

Functions for doing FEM analysis of gdsfactory/qnngds geometries

class qnngds.analysis.fem.Result(mesh, element, sigma, A, u)

Bases: object

Class for storing results of FEM simulation

__init__(mesh, element, sigma, A, u)

Constructor for Result

Parameters:

• mesh (MeshTri1) – skfem mesh (first-order triangular mesh)

• element (ElementTriP3) – piecewise cubic element

• sigma (np.ndarray) – conductivity for each dof

• A (scipy.sparse.csr_matrix) – discretized linear system

• u (dict[tuple[str,str], np.ndarray]) – solution vector for each port pair

qnngds.analysis.fem.get_squares(result: Result) → dict[str, float]

Calculate number of squares from result generated by solve_laplace

qnngds.analysis.fem.visualize_current(result: Result, port_pair: tuple[str, str], ax=None)

Visualize current density of result generated by solve_laplace

Parameters:

• result (Result) – result obtained from running solve_laplace on a mesh

• port_pair (tuple[str, str]) – pair of ports to visualize

• ax (plt.axis | None) – existing plot axis to add plot to if not None.

Returns:

(plt.axis)

qnngds.analysis.fem.visualize_mesh(mesh, ax=None)

Visualize mesh of wire/component

Parameters:

• mesh (MeshTri1) – scikit fem mesh

• ax (plt.axis | None) – existing plot axis to add plot to if not None.

Returns:

(plt.axis)

qnngds.analysis.fem.visualize_boundaries(mesh, ax=None)

Visualize boundaries of wire/component

Parameters:

• mesh (MeshTri1) – scikit fem mesh

• ax (plt.axis | None) – existing plot axis to add plot to if not None.

Returns:

(plt.axis)

qnngds.analysis.fem.make_mesh(device: Device, layer: str | int | tuple[int, int], tolerance: float = 0.01)

Generate a mesh from a qnngds.Device

Parameters:

• device (qnngds.Device) – input device to make a mesh of

• layer (LayerSpec) – layer of device to use.

• tolerance (float) – simplify tolerance for geometry to reduce mesh complexity

Returns:

(MeshTri1) mesh of the device

qnngds.analysis.fem.solve_laplace(mesh) → Result

Solve laplace equation for a meshed device

Parameters:

mesh (MeshTri1) – mesh of device

Returns:

(Result)

tdgl

Functions for interfacing with py-tdgl

qnngds.analysis.tdgl.make_tdgl_device(device: Device, coherence_length: float, london_lambda: float, thickness: float, gamma: float, layer: str | int | tuple[int, int]) → Device

Make a tdgl.Device that can be used for simulation from a gdsfactory Component

Parameters:

• device (qnngds.Device) – input device. Only one layer will be used, supports multiple ports, but regions must be contiguous(?)

• layer (LayerSpec) – layer of device to use.

• coherence_length (float) – coherence length of superconducting film in microns

• london_lambda (float) – london magnetic penetration depth in microns

• thickness (float) – thickness of the film in microns

• gamma (float) – material constant describing ratio of scattering time for electrons and phonons

Returns:

(tdgl.Device) –

a tdgl.Device instance that can be used with tdgl.solve() to model evolution of

order parameter and phase under application of bias current.

decorator

Define a registry for devices. Currently this is only used for documentation purposes.

qnngds.decorator.device(f)

Decorator to register DeviceFactories into the global variable qnngds.decorator._devices.

This is currently used for documentation purposes, however it would be nice to replicate some of the functionality of kfactory to overwrite the device name based on the arguments supplied to the function.

For example, if we wish to define a new DeviceFactory that can be used to generate Devices, we can write the following:

import qnngds as qg
from qnngds import Device

@qg.device
def my_new_device(
    some_param: int,
    some_other_param: str,
    layer: LayerSpec,
    ...
) -> Device:
    """Docstring to explain my function.

    Parameters
        some_param (int): explanation of some_param.
        some_other_param (str): explanation of some_other_param.
        layer (LayerSpec): GDS layer specification.
        ...

    Returns
        (Device): description of the device returned
    """
    ...

devices

Devices module contains variations of common devices used in the circuits designed by QNN group.

diode

Layout for superconducting diode [1].

qnngds.devices.diode.basic(width: float = 2, notch_depth: float = 1, notch_angle: float = 90, length: float = 5, mirror: bool = False, layer: LayerSpec = (1, 0)) → Device

Create notched vortex diode on single layer

Parameters:

• width (float) – wire width in microns

• notch_depth (float) – amount notch protrudes into wire

• notch_angle (float) – angle of notch opening in degrees

• length (float) – length of device

• mirror (bool) – if True, place notch on left side

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the diode

qnngds.devices.diode.gated(channel_spec: DeviceSpec = <function basic>, gate_spec: DeviceSpec = functools.partial(<function optimal_hairpin>, width=2, pitch=4, turn_ratio=2, layer=(10, 0))) → Device

Create notched vortex diode with a gate.

Lateral offset of the gate can be done by first offsetting the gate before passing it as an argument to this function.

Parameters:

• channel_spec (DeviceSpec) – what to use for diode channel (e.g. diode.basic)

• gate_spec (DeviceSpec) – what to use for top gate (e.g. geometries.optimal_hairpin)

Returns:

(Device) – the gated diode

htron

Heater cryotron devices [1], [2].

qnngds.devices.htron.heater(heater_spec: DeviceSpec = Device (name "nw_sharp" (uid 2), ports [1, 2], aliases [], 0 polygons, 1 references), pad_size: tuple[float, float] = (2, 2), pad_layer: LayerSpec = (20, 0)) → Device

Create a heater with superconducting leads for use with hTrons.

Parameters:

• heater_spec (DeviceSpec) – spec for heater

• pad_size (tuple[float, float]) – (width, height) of pad

• pad_layer (LayerSpec) – layer specification for top pads

Returns:

(Device) – a heater with pads

qnngds.devices.htron.multilayer(rotation: float = 0, channel_spec: DeviceSpec = functools.partial(<function variable_length>, constr_width=1, wire_width=2, length=4, symmetric=True, layer=(1, 0)), gate_spec: DeviceSpec = <function heater>) → Device

Create a multilayer hTron.

Parameters:

• rotation (float) – amount to rotate gate relative to channel.

• channel_spec (DeviceSpec) – callable function that generates a Device for the channel nanowire

• gate_spec (DeviceSpec) – callable function that generates a Device for the gate nanowire

Returns:

(Device) – a multilayer hTron

qnngds.devices.htron.planar(wire_width: int | float = 0.3, gate_width: int | float = 0.1, channel_width: int | float = 0.2, gap: int | float = 0.02, gate_length: int | float = 0.01, channel_length: int | float = 0.01, layer: LayerSpec = (1, 0)) → Device

Create a planar hTron.

Parameters:

• wire_width (int or float) – Width of routing wires in microns

• gate_width (int or float) – Width of superconducting gate in microns

• channel_width (int or float) – Width of superconducting channel in microns

• gap (int or float) – Spacing between gate and channel in microns

• gate_length (int or float) – Length of superconducting gate in microns

• channel_length (int or float) – Length of superconducting channel in microns

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – a single planar hTron

nanowire

Single nanowire constriction.

qnngds.devices.nanowire.sharp(constr_width: float = 0.1, wire_width: float = 0.3, length: float = 1, layer: LayerSpec = (1, 0)) → Device

Creates a single wire, made of two linear tapers starting at wire_width tapering down to constriction of width constr_width.

Parameters:

• constr_width (int or float) – The width of the channel (at the hot-spot location).

• wire_width (int or float) – The width of connections to source/drain

• length (int or float) – The length of the interior constriction.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – sharp constriction

qnngds.devices.nanowire.variable_length(constr_width: float = 0.1, wire_width: float = 0.3, length: float = 1, num_pts: int = 100, symmetric: bool = False, layer: LayerSpec = (1, 0)) → Device

Creates a single wire, made of two optimal steps from constr_width to wire_width with a constriction of the chosen length in the middle.

Parameters:

• constr_width (int or float) – The width of the channel (at the hot-spot location).

• wire_width (int or float) – The width of connections to source/drain

• length (int or float) – The length of the interior constriction.

• num_pts (int) – The number of points comprising the optimal_steps geometries.

• symmetric (bool) – if True, symmetric taper between constr_width and wire_width

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – 2 optimal steps to/from a narrow wire.

Raises:

ValueError if constr_width > wire_width –

ntron

Nanocryotron [1] variants.

qnngds.devices.ntron.sharp(choke_w: float = 0.03, gate_w: float = 0.2, channel_w: float = 0.1, source_w: float = 0.3, drain_w: float = 0.3, gate_sq: float = 2, channel_sq: float = 1, source_sq: float = 5, drain_sq: float = 5, layer: LayerSpec = (1, 0)) → Device

Creates a sharp ntron device.

Parameters:

• choke_w (float) – Width of the choke region.

• gate_w (float) – Width of the gate region.

• gate_sq (float) – Length of the gate region in squares.

• channel_w (float) – Width of the channel region.

• channel_sq (float) – Length of channel region in squares.

• source_w (float) – Width of the source region.

• source_sq (float) – Length of the source region in squares.

• drain_w (float) – Width of the drain region.

• drain_sq (float) – Length of the drain region in squares.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – The sharp ntron device.

qnngds.devices.ntron.slotted(base_spec: DeviceSpec = <function smooth>, slot_width: int | float = 0.04, slot_length: int | float = 1.5, slot_pitch: int | float = 0.08, n_slot: int = 2, num_pts: int = 100) → Device

Parallel-channel nanocryotron

See [1]

Parameters:

• base_spec (DeviceSpec) – callable function that generates a Device for the base nTron

• slot_width (int or float) – width of each slot

• slot_length (int or float) – length of each slot

• slot_pitch (int or float) – pitch of slots

• n_slot (int) – number of slots

• num_pts (int) – number of points to use for hairpin

Returns:

(Device) – nTron with slots

qnngds.devices.ntron.smooth(choke_w: float = 0.03, gate_w: float = 0.2, channel_w: float = 0.2, source_w: float = 0.3, drain_w: float = 0.3, choke_shift: float = -0.3, num_pts: int = 100, layer: LayerSpec = (1, 0)) → Device

Creates a ntron device.

Parameters:

• choke_w (float) – Width of the choke region.

• gate_w (float) – Width of the gate region.

• channel_w (float) – Width of the channel region.

• source_w (float) – Width of the source region.

• drain_w (float) – Width of the drain region.

• choke_shift (float) – Shift of the choke region.

• num_pts (int) – number of points to use for optimal steps

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – The ntron device.

resistor

Layouts for resistors and resistors with superconducting contacts.

qnngds.devices.resistor.meander(width: float = 2, pitch: float = 4, squares: float = 100, max_length: float | None = 20, layer: LayerSpec = (1, 0)) → Device

Create resistor meander with specified number of squares.

If squares*width > max_length or max_length is None, meander the resistor, destinationwise just return a straight line.

Parameters:

• width (float) – wire width in microns

• pitch (float) – desired pitch of meander in microns

• squares (float or None) – desired number of squares

• max_length (float) – desired length of device

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the resistor meander

qnngds.devices.resistor.meander_sc_contacts(width: float = 1, squares: float = 60, max_length: float | None = 10, meander_pitch: float | None = 2, contact_size: tuple[float, float] = (8, 3), outline_contacts: float = 1, layer_res: LayerSpec = 'PHOTO1', layer_contacts: LayerSpecs = ['EBEAM_FINE', 'PHOTO2'], layer_keepout: LayerSpecs = ['EBEAM_KEEPOUT']) → Device

Create resistor meander with superconducting contacts.

If squares*width > max_length or if max_length is None, meander the resistor.

Parameters:

• width (float) – width of resistor

• squares (float) – desired number of squares

• max_length (float or None) – maximum desired length of device

• meander_pitch (float or None) – desired pitch of meander in microns

• contact_size (tuple[float, float]) – (width, height) of resistor<->superconductor contact

• outline_contacts (float) – superconductor extra width on each side of contact

• layer_res (LayerSpec) – resistor GDS layer specification

• layer_contacts (LayerSpecs) – layer(s) for contact to superconductor (first will define port layer)

• layer_keepout (LayerSpecs) – layer(s) to do keepout on

Returns:

(Device) – the resistor meander

resonator

Layout for various superconducting resonators.

qnngds.devices.resonator.meandered(cross_section: CrossSectionSpec = <function cpw>, n_eff: float = 10, resonant_freq: float = 5000000000.0, meander_width: float = 500) → Device

Construct meandered half-wave resonator

Parameters:

• n_eff (float) – effective index of refraction

• resonant_freq (float) – resonant frequeny in Hz

• meander_width (float) – width of meander structure

• cross_section (CrossSectionSpec) – cross section to use (e.g. CPW)

Returns:

(Device) – meandered half-wave resonator

qnngds.devices.resonator.pad(width: float = 100, length: float = 200, edge_exclusion: float = 10, sc_layer: LayerSpec = 'PHOTO1', metal_layers: LayerSpecs = ('PHOTO2',)) → Device

Construct a pad for resonator with a metal layer for bonding on top of superconductor.

Parameters:

• width (float) – Desired width of superconductor layer

• edge_exclusion (float) – Amount on each side to decrease width of top metal bonding pad.

• sc_layer (LayerSpec) – layer specification for superconductor

• metal_layers (LayerSpecs) – layer(s) for metal

Returns:

(Device) – pad

qnngds.devices.resonator.straight(cross_section: CrossSectionSpec = <function cpw>, n_eff: float = 100, resonant_freq: float = 1000000000.0) → Device

Construct straight half-wave resonator

Parameters:

• cross_section (CrossSectionSpec) – cross section to use (e.g. CPW)

• n_eff (float) – effective index of refraction

• resonant_freq (float) – resonant frequeny in Hz

Returns:

(Device) – meandered half-wave resonator

qnngds.devices.resonator.transmission_line(cross_section: CrossSectionSpec = <function cpw>, length: float = 100) → Device

Construct a straight transmission line by extruding a cross section

Parameters:

• length (float) – length of transmission line

• cross_section (CrossSectionSpec) – cross section to extrude

Returns:

(Device) – straight transmission line

qnngds.devices.resonator.transmission_line_resonator(transmission_line_specs: tuple[DeviceSpec | None, DeviceSpec | None] = (<function transmission_line>, None), resonator_spec: DeviceSpec = <function meandered>, tl_cross_section: CrossSectionSpec = functools.partial(<function cpw>, width=75, gap=24), res_cross_section: CrossSectionSpec = <function cpw>, taper: DeviceFactory = <function hyper_taper>, pads: tuple[DeviceSpec | None, DeviceSpec | None] = (<function pad>, None), bbox_extension: float = 500) → Device

Construct a resonator embedded between two transmission lines

Inverts final design based on layer choice and PDK Layer class’s outline function

Parameters:

• transmission_line_specs (tuple[DeviceSpec | None, DeviceSpec | None]) – Desired DeviceSpec for transmission line on either end of resonator. If DeviceSpec, take a single argument cross_section. If None, no transmission line will be created (although the resonator will taper out to the width of the tl_cross_section.

• resonator_spec (DeviceSpec) – Desired DeviceSpec for embedded resonator. Must take a single argument cross_section.

• tl_cross_section (CrossSectionSpec) – CPW or microstrip cross section for transmission line.

• res_cross_section (CrossSectionSpec) – CPW or microstrip cross section for resonator.

• taper (DeviceFactory) – Callable which produces a Device, used to generate a filled taper between resonator and transmission line. Port widths must match. Should be solid (i.e. not outlined); will be automatically outlined for CPW.

• pads (tuple[DeviceSpec | None, DeviceSpec | None]) – DeviceSpec or None for each pad. If DeviceSpec, must take a single argument width. If None, no pad will be created

• bbox_extension (float) – amount to extend ground plane for negative tone layout CPW, or positive tone microstrip

Returns:

(Device) – resonator embedded between transmission lines

Example:

>>> from functools import partial
>>> tl_spec = partial(
>>>     qg.devices.resonator.transmission_line,
>>>     length=100,
>>> )
>>> res_spec = partial(
>>>     qg.devices.resonator.meandered,
>>>     n_eff=100,
>>>     resonant_freq=1e9,
>>>     meander_width=300,
>>> )
>>> tl_xc_spec = partial(
>>>     qg.devices.resonator.cpw,
>>>     width=20,
>>>     gap=4,
>>>     layer="PHOTO1",
>>> )
>>> res_xc_spec = partial(
>>>     qg.devices.resonator.cpw,
>>>     width=10,
>>>     radius=30,
>>>     gap=2,
>>>     layer="PHOTO1",
>>> )
>>> c = qg.devices.resonator.transmission_line_resonator(
>>>     transmission_line_specs=(tl_spec, None),
>>>     resonator_spec=res_spec,
>>>     tl_cross_section=tl_xc_spec,
>>>     res_cross_section=res_xc_spec,
>>>     taper=qg.geometries.hyper_taper,
>>>     pads=(qg.devices.resonator.pad, None),
>>>     bbox_extension=200,
>>> )

qnngds.devices.resonator.compute_veff(n_eff: float) → float

Computes effective light speed from effective index

Parameters:

n_eff – effective index of refraction

Returns:

(float) – effective phase velocity in m/s

qnngds.devices.resonator.compute_res_wavelength(n_eff: float, res_freq: float) → float

Computes resonant wavelength from effective index, resonant frequency.

Parameters:

• n_eff – effective index of refraction

• res_freq – resonant frequency in Hz

Returns:

(float) – resonant wavelength in microns

qnngds.devices.resonator.cpw(width: float = 10, gap: float = 5, radius: float = 50, layer: LayerSpec = 'PHOTO1') → CrossSection

Creates a coplanar waveguide (CPW) cross section.

NB resulting cross section is inverted: gaps will be filled and conductor will be empty.

Parameters:

• width (float) – width of center conductor

• gap (float) – width of gaps on either side of conductor

• radius (float) – bend radius

• layer (LayerSpec) – GDS layer specification

Returns:

(CrossSection) – CPW cross section

qnngds.devices.resonator.microstrip(width: float = 5, radius: float = 50, layer: LayerSpec = 'PHOTO1') → CrossSection

Creates a microstrip cross section

NB unlike cpw(), conductor is filled

Parameters:

• width (float) – width of center conductor

• radius (float) – bend radius

• layer (LayerSpec) – GDS layer specification

Returns:

(CrossSection) – microstrip cross section

snspd

Superconducting nanowire single photon detector geometries.

qnngds.devices.snspd.basic(wire_width: float = 0.2, wire_pitch: float = 0.6, size: Tuple[int | float | None, int | float | None] = (5, 5), num_squares: int | None = None, turn_ratio: int | float = 4, num_pts: int = 50, extend_terminals: bool = True, terminals_same_side: bool = False, layer: LayerSpec = (1, 0)) → Device

Creates an optimally-rounded SNSPD.

Modification of gdsfactory’s and phidl’s implementations

Parameters:

• wire_width (float) – Width of the nanowire.

• wire_pitch (float) – Pitch of the nanowire.

• size (tuple of Optional[int or float]) – Size of the detector.

• num_squares (int | None) – Number of squares in the detector.

• turn_ratio (int or float) – Specifies how much of the SNSPD width is dedicated to the 180 degree turn. A turn_ratio of 10 will result in 20% of the width being comprised of the turn.

• num_pts (int) – number of polygon points to use for turn

• extend_terminals (bool) – If True, bring ports flush to edges of device

• terminals_same_side (bool) – If True, both ports will be located on the same side of the SNSPD.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – optimally-rounded SNSPD, as provided by Phidl but renamed and unified.

qnngds.devices.snspd.vertical(wire_width: float = 0.2, wire_pitch: float = 0.6, size: Tuple[int | float, int | float] = (5, 5), num_squares: int | None = None, extend: float | None = 1, num_pts: int = 50, layer: LayerSpec = (1, 0)) → Device

Creates an optimally-rounded SNSPD, with terminals in its center instead of the side.

Parameters:

• wire_width (float) – Width of the nanowire.

• wire_pitch (float) – Pitch of the nanowire.

• size (tuple of int or float) – Size of the detector.

• num_squares (int | None) – Number of squares in the detector.

• extend (bool | None) – Whether or not to extend the ports.

• num_pts (int) – number of points to use for optimal hairpin.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – The vertical SNSPD device.

experiment

Utilities for generating experiments from devices or circuits, automatically routing between device/circuit and pads and performing outlining and boolean keepout operations based on PDK requirements.

class qnngds.experiment.RouteGroup(cross_section: CrossSectionSpec, port_mapping: dict | tuple, ground: bool = False)

Bases: object

Stores information for routing DUTs to pads.

Stores a cross section and mapping of DUT ports to optional pad ports. If a DUT port is mapped to None, then a pad port will be automatically assigned in generate_experiment()

__init__(cross_section: CrossSectionSpec, port_mapping: dict | tuple, ground: bool = False)

Initialize route group

Parameters:

• cross_section (CrossSectionSpec) – factory method for desired cross section used for routing

• port_mapping (dict | tuple) – either dictionary manually specifying mapping of DUT port names to pad port names or a tuple of DUT port names that should be mapped automatically to pad ports.

• ground (bool) – If True, then all dut ports will not be connected to a pad port. This allows connection to ground plane for positive-tone layouts.

Returns:

None

qnngds.experiment.generate(dut: DeviceSpec | Device, pad_array: DeviceSpec | Device, label: DeviceSpec | Device | None, route_groups: Sequence[RouteGroup] | None, dut_offset: tuple[float, float] = (0, 0), pad_offset: tuple[float, float] = (0, 0), label_offset: tuple[float, float] | None = (-100, -100), ignore_port_count_mismatch: bool = False, ignore_dut_bbox: bool = False, retries: int = 10) → Device

Construct an experiment from a device/circuit (Device).

Includes text, pads, and routing to connect pads to devices

Parameters:

• dut (DeviceSpec or Device) – finished device to be connected to pads

• pad_array (DeviceSpec or Device or None) – pad array to connect to device

• label (DeviceSpec or Device or None) – text label or factory.

• route_groups (Sequence[RouteGroup] or None) – how to route DUT to pads

• dut_offset (tuple[float, float]) – x,y offset for dut (mostly useful for linear pad arrays)

• pad_offset (tuple[float, float]) – x,y offset for pad array (mostly useful for linear pad arrays)

• label_offset (tuple[float, float] or None) – x,y offset of label

• ignore_port_count_mismatch (bool) – if True, ignores mismatched number of DUT and pads ports, only if route_groups defines a mapping to all pad ports, or lists all DUT ports.

• ignore_dut_bbox (bool) – if True, does not attempt to route around DUT bounding box (bbox)

• retries (int) – how many times to try rerouting with s_bend (may need to be larger for many port groupings)

Returns:

(Device) – experiment

Example

Using the example qnngds PDK: https://github.com/qnngroup/qnngds-pdk/, we can generate an example nTron test layout including pads. The pad array is just a linear array from gdsfactory, although a custom array could be defined. The mapping of nTron device ports to pad ports is defined manually with route_groups, but it’s possible to use autoassignment by setting route_groups=None. However, autoassignment only works in some cases, and in the case of this nTron, it would most likely fail.

>>> c = qg.experiment.generate(
>>>     dut=qg.devices.ntron.sharp,
>>>     pad_array=qg.pads.array(
>>>         pad_specs=(qg.pads.stack(size=(200, 200), layers=("EBEAM_COARSE",)),),
>>>         columns=1,
>>>         rows=3,
>>>         pitch=250,
>>>     ),
>>>     label=None,
>>>     route_groups=(
>>>         qg.experiment.RouteGroup(
>>>             qg.get_cross_section("ebeam"), {"g": 2, "s": 1, "d": 3}
>>>         ),
>>>     ),
>>>     dut_offset=(250, 250),
>>>     pad_offset=(0, 0),
>>>     label_offset=(0, 0),
>>>     retries=1,
>>> )
>>> qp(c)

geometries

Geometries contains useful shapes/tools that are not available in phidl’s geometry library.

qnngds.geometries.angled_taper(end_width: int | float = 0.2, start_width: int | float = 0.1, angle: int | float = 60, layer: LayerSpec = (1, 0)) → Device

Create an angled taper with euler curves.

Parameters:

• end_width (int or float) – Width of wide end of taper

• start_width (int or float) – Width of narrow end of taper

• angle (int or float) – Angle between taper ends in degrees

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – a single taper

qnngds.geometries.euler_taper(start_width: int | float = 5, end_width: int | float = 50, layer: LayerSpec = (1, 0), num_points: int = 200) → Device

Euler taper (solid). Designed by reedf.

Parameters:

• length (int | float) – Length of taper

• start_width (int | float) – Width of start of taper

• end_width (int | float) – Width of end of taper

• layer (LayerSpec) – GDS layer specification

• num_points (int) – number of points to use

Returns:

(Device) – a single taper

qnngds.geometries.fillet_90deg(size: tuple[float, float] = (4, 2), stub_size: tuple[float, float] = (2, 1), taper_type: str | None = 'fillet', taper_radius: float | None = None, layer: LayerSpec = (1, 0)) → Device

Creates a 90 degree with fillet bend. Adapted from phidl.flagpole

Parameters:

• size (array-like) – (width, height) of the flag.

• stub_size – (array-like): (width, height) of the pole stub.

• taper_type (str | None) – {‘straight’, ‘fillet’, None} Type of taper between the bottom corner of the stub on the side of the flag and the corner of the flag closest to the stub.

• taper_radius (float | None) – radius of taper. If None, uses stub_size

• layer (LayerSpec) – Specification of layer(s) to put polygon geometry on.

Returns:

(Device) – tee

qnngds.geometries.fine_to_coarse(width1: float = 2.0, width2: float = 20.0, layer1: LayerSpec = 'EBEAM_FINE', layer2: LayerSpec = 'EBEAM_COARSE') → Device

Create transition between fine and coarse layers.

Automatically performs outlining for positive-tone resist.

Parameters:

• width1 (float) – starting width on first layer

• width2 (float) – ending width on second layer

• layer1 (LayerSpec) – layer specification for first layer

• layer2 (LayerSpec) – layer specification for second layer

Returns:

(Device) – transition between fine and coarse layers

qnngds.geometries.hyper_taper(length: int | float = 10, start_width: int | float = 5, end_width: int | float = 50, layer: LayerSpec = (1, 0), num_points: int = 50) → Device

Hyperbolic taper (solid). Designed by colang.

Parameters:

• length (int or float) – Length of taper

• start_width (int or float) – Width of start of taper

• end_width (int or float) – Width of end of taper

• layer (LayerSpec) – GDS layer specification

• num_points (int) – number of points to use

Returns:

(Device) – a single taper

qnngds.geometries.optimal_hairpin(width: float | int = 0.2, pitch: float | int = 0.6, length: float | int = 10, turn_ratio: float | int = 4, num_pts: float | int = 50, layer: LayerSpec = (1, 0)) → qg.Device

Returns an optimally-rounded hairpin geometry, with a 180 degree turn.

based on phidl.geometry. Used instead of phidl implementation to center the apex of the hairpin at (0, 0).

Parameters:

• width – Width of the hairpin leads.

• pitch – Distance between the two hairpin leads. Must be greater than width.

• length – Length of the hairpin from the connectors to the opposite end of the curve.

• turn_ratio – int or float Specifies how much of the hairpin is dedicated to the 180 degree turn. A turn_ratio of 10 will result in 20% of the hairpin being comprised of the turn.

• num_pts – Number of points constituting the 180 degree turn.

• layer – Specific layer(s) to put polygon geometry on.

Notes

Hairpin pitch must be greater than width.

Optimal structure from https://doi.org/10.1103/PhysRevB.84.174510 Clem, J., & Berggren, K. (2011). Geometry-dependent critical currents in superconducting nanocircuits. Physical Review B, 84(17), 1-27.

qnngds.geometries.taper(length: int | float = 10, start_width: int | float = 5, end_width: int | float = 2, layer: LayerSpec = (1, 0)) → Device

Linear taper (solid).

Parameters:

• length (int or float) – Length of taper

• start_width (int or float) – Width of first end of taper

• end_width (int or float) – Width of second end of taper

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – a single taper

qnngds.geometries.tee(size: tuple[float, float] = (4, 2), stub_size: tuple[float, float] = (2, 1), taper_type: str | None = 'fillet', taper_radius: float | None = None, layer: LayerSpec = (1, 0)) → Device

Creates a T-shaped geometry.

Adapted from phidl and adds additional argument to specify the radius of fillet tapers.

Parameters:

• size (array-like) – (width, height) of the tee.

• stub_size – (array-like): (width, height) of the stub.

• taper_type (str | None) – {‘straight’, ‘fillet’, None} Type of taper between the bottom corner of the stub on the side of the flag and the corner of the flag closest to the stub.

• taper_radius (float | None) – radius of taper. If None, uses stub_size

• layer (LayerSpec) – Specification of layer(s) to put polygon geometry on.

Returns:

(Device) – tee

qnngds.geometries.via(size: tuple[float, float] = (5, 5), via_undersize: float = 0.5, layer_bottom: LayerSpec = (1, 0), layer_via: LayerSpec = (10, 0), layer_top: LayerSpec = (20, 0)) → Device

Creates a via between two layers

Parameters:

• size (tuple[float, float]) – width, height of top/bottom pads

• via_undersize (float) – amount on each side to compensate overetch of via

• layer_bottom (LayerSpec) – bottom layer specification

• layer_via (LayerSpec) – via layer specification

• layer_top (LayerSpec) – top layer specification

Returns:

(Device) – via

qnngds.geometries.default_cross_section(width: float = 25, layer: LayerSpec = (1, 0), radius: float = 30.0, force_no_outline: bool = False) → CrossSection

Return a default cross_section.

Parameters:

• width (float) – width of cross section

• layer (LayerSpec) – layer specification for cross section

• radius (float) – bend radius

• force_no_outline (bool) – if True, ignores if layer is positive tone.

Returns:

(CrossSection)

layout

Extend phidl’s Layout classes:

Modifications:

• Port: add layer information

• CellArray: add ports

• Layer: add outline/keepout info

• CrossSection: allow “hidden” sections

class qnngds.layout.Port(name: str = None, midpoint: ArrayLike = (0, 0), width: float = 1, orientation: float = 0, layer: LayerSpec = (1, 0), parent=None)

Bases: Port

Port object used to snap objects together. Extends phidl.Port to add layer information

__init__(name: str = None, midpoint: ArrayLike = (0, 0), width: float = 1, orientation: float = 0, layer: LayerSpec = (1, 0), parent=None) → None

Constructor for Port.

Parameters:

• name (str) – name of port

• midpoint (np.ArrayLike) – midpoint of port location

• width (float) – width of float

• orientation (float) – rotation of port

• layer (LayerSpec) – GDS layer specification

• parent

class qnngds.layout.Device(*args, **kwargs)

Bases: Device

The basic object that holds polygons, labels, and ports in PHIDL. Augmented with methods for layer-assigned ports.

add_port(name: str = None, midpoint: ArrayLike = (0, 0), width: float = 1, orientation: float = 0, layer: LayerSpec = None, port: Port | None = None) → Port

Adds a Port to the Device.

Parameters:

• name (str) – name of port

• midpoint (tuple[float,float]) – midpoint of port location

• width (float) – width of float

• orientation (float) – rotation of port

• layer (LayerSpec) – GDS layer specification

• port (Port | None) – a Port if the added Port is a copy of an existing Port.

Notes

Can be called to copy an existing port like add_port(port = existing_port) or to create a new port add_port(myname, mymidpoint, mywidth, myorientation, mylayer). Can also be called to copy an existing port with a new name like add_port(port = existing_port, name = new_name)

Returns:

(Port) – created port

add_ports(ports: Sequence[Port]) → None

Add multiple Ports to Device

Parameters:

ports (Sequence[Port]) – multiple Port objects to be added

add_array(device: Device, columns: int = 2, rows: int = 2, spacing: tuple[float, float] = (100, 100), alias: str | None = None) → DeviceArray

Creates a DeviceArray reference.

Parameters:

• device (Device) – the referenced Device.

• columns (int) – number of columns in the array.

• rows (int) – number of rows in the array.

• spacing (Arraylike) – (column spacing, row spacing)

• alias (str | None) – Alias of the referenced Device.

Returns:

(DeviceArray) – array containing references to the input Device.

name

polygons

paths

labels

references

class qnngds.layout.DeviceArray(*args, **kwargs)

Bases: CellArray

Augmentation of gdspy/phidl’s CellArray class, autogenerates a port dictionary for all instances

__init__(*args, **kwargs) → None

Calls PHIDL constructor for CellArray, then generates ports for each reference in array

columns

rows

rotate(angle=45, center=(0, 0)) → None

Rotate underlying CellArray and update ports

Parameters:

• angle (float) – rotation angle

• center (Arraylike) – coordinates about which to perform rotation

move(origin=(0, 0), destination=None, axis=None) → None

Translate underlying CellArray and update ports

Parameters:

• origin (tuple) – starting location

• destination (Arraylike | None) – destination

• axis

ref_cell

origin

rotation

magnification

x_reflection

spacing

properties

class qnngds.layout.Layer(gds_layer: int = 0, gds_datatype: int = 0, name: str = 'unnamed', description: str | bool = None, inverted: bool = False, color: str | tuple | None = None, alpha: int | float = 0.6, dither: str | None = None, keepout: LayerSpecs | Sequence[Layer] | None = None, outline: int | float = 0)

Bases: Layer

Augment PHIDL Layer with outline and keepout information

__init__(gds_layer: int = 0, gds_datatype: int = 0, name: str = 'unnamed', description: str | bool = None, inverted: bool = False, color: str | tuple | None = None, alpha: int | float = 0.6, dither: str | None = None, keepout: LayerSpecs | Sequence[Layer] | None = None, outline: int | float = 0) → None

Constructor for qnngds.Layer

Parameters:

• keepout (LayerSpecs | Layers | None) – if not None, defines one or more Layers for which the current layer defines keepout regions.

• outline (int | float) – if non-zero, makes layer positive tone, written with a linewidth of outline.

class qnngds.layout.LayerSet

Bases: LayerSet

Augment PHIDL LayerSet to use Layers with outline and keepout information

add_layer(layer: Layer) → None

Add a layer to the LayerSet

Parameters:

layer (Layer) – layer to add

class qnngds.layout.CrossSection(radius: int | float = 0)

Bases: CrossSection

Augment PHIDL CrossSection to allow for hidden layers and radius specification

__init__(radius: int | float = 0) → None

Constructor for CrossSection

Parameters:

radius (float | int) – nominal radius used when autogenerating paths. NB explicitly providing a radius (e.g. when manually creating paths) will override this setting

add(width: float | int = 1, offset: float | int = 0, layer: int | tuple[int, int] = 0, ports: tuple[int | str | None] = (None, None), name: str | None = None, hidden: bool = False, min_radius: float | int = 0) → CrossSection

Calls phidl.CrossSection.add() method, and also updates hidden variable

Parameters:

• width (float | int | callable) – Width of the segment

• offset (float | int | callable) – Offset of the segment (positive values = right hand side)

• layer (int | tuple[int, int]) – The polygon layer to put the segment on

• ports (array-like[2] of str | int | None) – If not None, specifies the names for the ports at the ends of the cross-sectional element.

• name (str | int | None) – Name of the cross-sectional element for later access

• hidden (bool) – if True, does not add polygon during extrusion

Returns:

(CrossSection) – updated self

extrude(path: Path, simplify=None) → Device

Calls phidl.CrossSection.extrude() method and removes any polygons corresponding to hidden layers

Parameters:

• path (Path) – path to extrude along

• simplify (float | None) – simplify ratio

Returns:

(Device) – extruded cross section

qnngds.layout.to_qg_device(device: phDevice, layer: LayerSpec) → Device

Converts a phidl.Device to a qnngds.Device

Parameters:

• device (phidl.Device) – device to convert

• layer (LayerSpec) – layer to use for all ports

Returns:

(qnngds.Device) – Device with layer-assigned ports.

pads

Pads contains functions for generation of pads and pad arrays.

qnngds.pads.array(pad_specs: DeviceSpecs = (<function stack>, ), columns: int = 1, rows: int = 3, pitch: float = 150) → Device

Creates a linear array of pads

Parameters:

• pad_spec (DeviceSpec) – specification for pad or pad stack to use

• columns (int) – number of columns

• rows (int) – number of rows

• pitch (float) – pitch of pads (same for rows/columns)

Returns:

(Device) – linear pad array

qnngds.pads.quad_line(array_spec: DeviceSpec = <function array>, port_width: float = 20, port_pitch: float = 50, port_offset: tuple[float, float] = (100, 0)) → Device

Create pads with quad routing to intermediate ports

Parameters:

• array_spec (DeviceSpec) – spec for pad array (assumes 1D array along y-axis)

• port_width (float) – width of intermediate ports

• port_pitch (float) – pitch of intermediate ports

• port_offset (tuple[float, float]) – offset of intermediate ports relative to pad array port center

Returns:

(Device) – pads with intermediate finer ports

qnngds.pads.stack(size: tuple[float, float] = (200, 100), layers: LayerSpecs = ('EBEAM_COARSE',), port_span: tuple[float, float] = (0, 1)) → Device

Create pad stack for use in other pad arrays

Has a single port facing to the right

Parameters:

• size (tuple[float, float]) – width, height of pad

• layers (LayerSpecs) – One or more layers to stack. First layer will have a port, which is the layer that will be used for routing to the pad.

• port_span (tuple[float, float]) – fraction on [0,1] for starting and ending point of port

Returns:

(Device) – pad stack

qnngds.pads.vdp(pad_specs: DeviceSpecs = (<function stack>, ), space: float = 500) → Device

Create pads for Van der Pauw probing

Parameters:

• pad_specs (DeviceSpecs) – specification for pad or pad stack to use. Can be a single element tuple or 4 different pads.

• space (float) – Spacing between pads (diagonal of VDP cell)

Returns:

(Device) – Van der Pauw pad structure

pdk

Pdk functions for layer and device management, mostly taken from gdsfactory

class qnngds.pdk.Pdk(name: str, layers: LayerSet, cross_sections: dict[str, CrossSection] = {}, layer_transitions: dict[LayerSpec | tuple[LayerSpec, LayerSpec], DeviceSpec] = {}, devices: DeviceSpecs = [])

Bases: object

PDK class, stores layer information, cross sections, layer transistions, and devices

__init__(name: str, layers: LayerSet, cross_sections: dict[str, CrossSection] = {}, layer_transitions: dict[LayerSpec | tuple[LayerSpec, LayerSpec], DeviceSpec] = {}, devices: DeviceSpecs = []) → None

Constructor

Parameters:

• name (str) – name of PDK

• layers (LayerSet) – LayerSet to use for PDK

• cross_sections (dict[str, CrossSection]) – map of named cross sections to their instances.

• layer_transitions (dict[LayerSpec | tuple[LayerSpec, LayerSpec], DeviceSpec]) – map of LayerSpec (or pair of LayerSpecs) to a DeviceSpec which will transition between layers.

• devices (DeviceSpecs) – devices to register with PDK

Returns:

None

activate() → None

Enable the PDK and allow it to be accessed globally

get_layer(layer: LayerSpec) → Layer

Get a specific layer within the PDK

Parameters:

layer (LayerSpec) – string, int, or tuple that identifies the desired layer

Returns:

(Layer) – instance of layer matching the queried LayerSpec

get_device(spec: DeviceSpec, **kwargs: dict) → phidl.Device

Get a specific device within the PDK

Parameters:

• spec (DeviceSpec) – device instance, name (string), or callable function that identifies desired device

• kwargs (dict) – keyword arguments to pass to spec.

Returns:

(Device) – instance of device matching the queried DeviceSpec

get_cross_section(spec: CrossSectionSpec) → phidl.CrossSection

Get a specific layer within the PDK

Parameters:

spec (CrossSectionSpec) – device instance, name (string), or callable function that identifies desired device

Returns:

(CrossSection) – instance of device matching the queried CrossSectionSpec

qnngds.pdk.get_active_pdk() → Pdk

Get the globally-activated PDK

qnngds.pdk.get_generic_pdk() → Pdk

Get a generic PDK

Includes the following layers: * EBEAM_FINE (1, 0), outline=0.1 * EBEAM_COARSE (2, 0), outline=10 * EBEAM_KEEPOUT (3, 0), keepout=(EBEAM_FINE,) * PHOTO1 (10, 0) * PHOTO2 (20, 0) * PHOTO3 (30, 0) * PHOTO4 (40, 0)

Includes the following cross-sections for routing: * ebeam (EBEAM_COARSE) * photo1 (PHOTO1) * photo2 (PHOTO2) * photo3 (PHOTO3) * photo4 (PHOTO4)

Includes the following layer transitions: * EBEAM_FINE <-> EBEAM_COARSE * all transitions within the same layer

qnngds.pdk.get_layer(layer: LayerSpec) → Layer

Get a specific layer within the globally-activated PDK

Parameters:

layer (LayerSpec) – string, int, or tuple that identifies the desired layer

Returns:

(Layer) – instance of layer matching the queried LayerSpec

qnngds.pdk.get_device(spec: DeviceSpec, **kwargs: dict) → phidl.Device

Get a specific layer within the globally-activated PDK

Parameters:

• spec (DeviceSpec) – device instance, name (string), or callable function that identifies desired device

• kwargs (dict) – Keyword arguments to pass to spec.

Returns:

(Device) – instance of device matching the queried DeviceSpec

qnngds.pdk.get_cross_section(cross_section: CrossSectionSpec) → phidl.CrossSection

Get a specific layer within the globally-activated PDK

Parameters:

cross_section (CrossSectionSpec) – cross_section instance, name (string), or callable function that identifies desired cross_section

Returns:

(CrossSection) – instance of cross_section matching the queried CrossSectionSpec

qnngds.pdk.layer_auto_transitions(layer_set: LayerSet) → dict[LayerSpec, DeviceSpec]

Generate layer_transitions dictionary for auto tapers within the same layer

Parameters:

layer_set (LayerSet) – layers in PDK for which the auto transitions should be generated

Returns:

(dict[Layer, DeviceSpec]) – mapping the appropriate taper for each layer auto transitions

sample

Sample defines the Sample class which is used to generate a wafer/piece layout from multiple experiments

qnngds.sample.piece10mm()

Template for 10 mm piece

qnngds.sample.wafer100mm() → Device

Template for 100 mm wafer

qnngds.sample.wafer150mm() → Device

Template for 150 mm wafer

exception qnngds.sample.PlaceError(message)

Bases: Exception

Exception raised when placement fails

__init__(message)

Constructor for PlaceError

Parameters:

message (str) – error message

class qnngds.sample.Sample(cell_size: float = 10000, sample: DeviceSpec | Device = <function wafer100mm>, edge_exclusion: float = 10000, allow_cell_span: bool = False)

Bases: object

Class for managing die/experiment area, with manual placement and basic autoplacement

Defines a grid size and divides a sample (wafer/piece) into cells. Experiments (generated with qnngds.utilities.generate_experiment()) can be placed on one or more cells in the grid, manually or automatically. If initialized with allow_cell_span, experiments can span multiple columns/rows.

For a wafer, it is recommended to have two hierarchies of Sample s. At the top-level, define a wafer-sized Sample, with a number of cells that can be cut/cleaved into dies. Each cell may be defined as a Sample to place multiple experiments on a grid within the die. For example:

>>> my_experiment_die_1 = qg.sample.Sample(
>>>     cell_size=1e3, sample=qg.sample.piece10mm, edge_exclusion=500, allow_cell_span=True,
>>> )
>>> # place experiments (e.g. circuits, devices, lithographic structures etc.) on nTron_die
>>> # ...
>>> # create other dies
>>> # ...
>>> # ...
>>> sample = qg.sample.Sample(
>>>     cell_size=10e3, sample=qg.sample.wafer100mm, edge_exclusion=10e3, allow_cell_span=False,
>>> )
>>> # place nTron_die and other dies on sample

__init__(cell_size: float = 10000, sample: DeviceSpec | Device = <function wafer100mm>, edge_exclusion: float = 10000, allow_cell_span: bool = False) → None

Constructor for Sample class

Parameters:

• cell_size (float) – pitch of cell grid

• sample (Device | DeviceSpec) – desired sample shape (e.g. wafer/piece)

• edge_exclusion (float) – desired edge exclusion for die placement

• allow_cell_span (bool) – if True, allows a device added to the sample to span multiple cells

Returns:

None

visualize_open_cells() → Device

Visualize open cells

Returns:

(Device) – device used for visualization

place_on_sample(device: Device, cell_coordinate_bbox: tuple, ignore_collisions: bool = False) → None

Place device on sample

See also place_multiple_on_sample().

Parameters:

• device (Device) – device to place

• cell_coordinate_bbox (tuple[int, int] | tuple[tuple[int, int], tuple[int, int]]) – bounding box of cell coordiantes within which the device should be placed. If the device fits within a single cell, then a tuple[int, int] is acceptable instead of passing a tuple with identical coordinates for the bbox. If device spans multiple cells, then the bbox coordinates must be unique.

• ignore_collisions (bool) – If True, ignores any collision of device with previously-placed devices.

Returns:

None

Side Effects:

Updates self.open_cells to remove newly allocated cells Updates self.full_cells to add newly allocated cells

place_multiple_on_sample(devices: Sequence[Device], cell_coordinate_bbox: tuple, column_major: bool = True, ignore_collisions: bool = False) → None

Place devices on sample

See also place_on_sample().

Parameters:

• devices (Sequence[Device]) – sequence of devices to place

• cell_coordinate_bbox (tuple[tuple[int, int], tuple[int, int]]) – bounding box of cell coordiantes within which the device should be placed.

• column_major (bool) – If True, orders devices in column-major order within bbox. (top-to-bottom, then left-to-right). Otherwise, orders row-major (left-to-right, then top-to-bottom).

• ignore_collisions (bool) – If True, ignores any collision of device with previously-placed devices.

Returns:

None

Side Effects:

Updates self.open_cells to remove newly allocated cells Updates self.full_cells to add newly allocated cells

write_cell_corners(width: float, layer: LayerSpec) → None

Adds corner markers to all full cells

Parameters:

• width (float) – width of corner marker

• layer (LayerSpec) – marker’s layer specification

Returns:

None

Side Effects:

Updates self.devices with the new markers

write_cell_labels(size: float, layer: LayerSpec, inset_dist: float, location: int) → None

Adds text label to all cells

Parameters:

• size (float) – text size

• layer (LayerSpec) – text’s layer specification

• inset_dist (float) – distance between label and corner

• location (int) – 0 -> NW, 1 -> NE, 2 -> SE, 3 -> SW

Returns:

None

Side Effects:

Updates self.devices with the new labels

write_alignment_marks(marker_spec: DeviceSpec | Device, location: tuple[float, float]) → None

Adds alignment markers

Parameters:

• marker_spec (DeviceSpec | Device) – marker to use (e.g. cross)

• location (tuple[float, float]) – location of top-right alignment mark. makes symmetric alignment marks about origin (0, 0)

Returns:

None

Side Effects:

Updates self.devices with the alignment markers

num_full_cells() → int

Get number of cells in sample that are filled

num_open_cells() → int

Get number of cells in sample that are open

test_structures

Teststructures contains lithographic and electrical test structures.

qnngds.test_structures.alignment_mark(layer1: LayerSpec = (1, 0), layer2: LayerSpec = (10, 0)) → Device

Creates vernier caliper comb between two layers.

Helper method for alignment_mark.

Parameters:

• layer1 (LayerSpec) – center comb GDS layer specification

• layer2 (LayerSpec) – top/bottom comb GDS layer specification

Returns:

(Device) – alignment cross with vernier calipers

qnngds.test_structures.circ_tlm(ext_radius: float = 100, int_radius: List[float] = [50, 70, 80, 90, 95, 98, 99], pad_layer: LayerSpec = (20, 0), mesa_layers: LayerSpecs = [(1, 0), (10, 0)], text_size: float = 10) → Device

Creates rectangular transfer-length-method test structures.

Parameters:

• ext_radius (float) – external radius of hole that defines outer pad

• int_radius (List[float]) – list of internal radii. The gap is d = ext_radius - int_radius.

• pad_layer (LayerSpec) – layer specification for probable pads.

• mesa_layers (LayerSpecs) – layer(s) for bottom metal/semiconductor and/or vias

• text_size (float) – size of text label

Returns:

(Device) – TLM structure

qnngds.test_structures.cross_bridge_kelvin_resistor(size: float = 50, lead_length: float = 50, layer_top: LayerSpec = 'PHOTO1', layer_bot: LayerSpec = 'EBEAM_COARSE', layer_via: LayerSpec | None = 'PHOTO2') → Device

Generate a cross-bridge Kelvin resistor.

See this paper.

Parameters:

• size (float) – side length of square junction

• lead_length (float) – length of leads to junction

• layer_top (LayerSpec) – layer specification of top conductor

• layer_bot (LayerSpec) – layer specification of bottom conductor

• layer_via (LayerSpec | None) – if not None, create via on specified layer

Returns:

(Device) – cross-bridge Kelvin resistor

qnngds.test_structures.dose_defocus(resolutions: tuple[float] = (0.7, 0.8, 0.9, 1.0), layer: LayerSpec = 'PHOTO1') → Device

Generate a test structure for doing dose/defocus tests

Contains a lithographic checkerboard, stars, crossed lines, and waffles.

Parameters:

• layer (LayerSpec) – layer to put pattern on

• resolutions (tuple[float]) – resolutions to use for star, crossed lines and waffles. Resolution for litho checkerboard is determined automatically from maximum element.

Returns:

(Device) – dose defocus test structure.

qnngds.test_structures.etch_test(layer: LayerSpec = (1, 0), pad_size: tuple[float, float] = (2000, 2000), trench_width: float = 20) → Device

Construct side-by-side pads for performing electrical etch tests.

Parameters:

• layer (LayerSpec) – GDS layer specification

• pad_size (tuple[float, float]) – width, height of each pad

• trench_width (float) – width of trench around each pad

Returns:

(Device) – etch test structure

qnngds.test_structures.multilayer_alignment(layers: LayerSpecs = ['PHOTO1', 'PHOTO2', 'PHOTO3']) → Device

Creates an alignment mark for each lithography layer.

Parameters:

layers (LayerSpecs) – A list of GDS layer specifications

Returns:

(Device) – alignment marks between each layer pair

qnngds.test_structures.rect_tlm(contact_l: float = 10, spacings: List[float] = [10, 10, 20, 50, 80, 100, 200], contact_w: float = 100, via_layer: LayerSpec | None = (1, 0), finger_layer: LayerSpec = (10, 0), pad_layer: LayerSpec | None = (10, 0), mesa_layer: LayerSpec = (20, 0), pad_size: Tuple[float, float] = (80, 80)) → Device

Creates rectangular transfer-length-method test structures.

Parameters:

• contact_l (float) – length of metal contact on semiconductor

• spacings (List[float]) – list of spacings between contacts

• contact_w (float) – width of contact/semiconductor

• via_layer (LayerSpec | None) – layer specification for via between mesa and fingers. If None, don’t include via.

• finger_layer (LayerSpec) – layer for fingers that periodically contact mesa

• pad_layer (LayerSpec | None) – layer for probable pads. If None, don’t include.

• mesa_layer (LayerSpec) – layer for semiconductor

• pad_size (tuple(float,float)) – width, height of pad

Returns:

(Device) – TLM structure

qnngds.test_structures.resolution_L(res: float | int = 1, layer: LayerSpec = (1, 0)) → Device

Creates L-shaped test structures for determining process resolution.

Helper method for resolution_test.

Parameters:

• res (float or int) – Resolution (in µm) to be tested.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the resolution test structure

qnngds.test_structures.resolution_checkerboard(resolutions: List[float] = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0], layer: LayerSpec = (1, 0), label_interval: int = 5, label_size: float = 10) → Device

Creates crossed lith_steps pattern for lithographic resolution test.

Parameters:

• resolutions (List[float]) – List of resolutions (in µm) to be tested.

• layer (LayerSpec) – GDS layer specification

• label_interval (bool) – how often to label (set to 0 to disable all labels)

• label_size (float) – size of text label

Returns:

(Device) – the litho test structure

qnngds.test_structures.resolution_steps(resolutions: List[float] = [0.3, 0.4, 0.5, 0.6, 0.7, 0.8], width: float = 5, spacing: float = 5, layer: LayerSpec = (1, 0)) → Device

Creates step pattern for lithographic resolution test.

Adapted from PHIDL.

Parameters:

• resolutions (List[float]) – List of resolutions (in µm) to be tested.

• width (float) – width of stripes

• spacing (float) – spacing between stripes

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the test structure

qnngds.test_structures.resolution_test(resolutions: List[float] = [0.6, 0.8, 1.0], outline: float | None = None, layer: LayerSpec = (1, 0)) → Device

Creates L and waffle structures for determining process resolution.

Parameters:

• resolutions (List[float]) – List of resolutions (in µm) to be tested.

• outline (Optional[float]) – If none, do not invert. If zero, invert the device, otherwise outline the device by this width.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the resolution test structures

qnngds.test_structures.resolution_waffle(res: float | int = 1, layer: LayerSpec = (1, 0)) → Device

Creates resolution_waffle test structures for determining process resolution.

Helper method for resolution_test.

Parameters:

• res (float or int) – Resolution (in µm) to be tested.

• layer (LayerSpec) – GDS layer specification

Returns:

(Device) – the resolution test structure

qnngds.test_structures.vdp(diagonal: float = 400, contact_width: float = 40, layer: LayerSpec = (1, 0), port_type: str = 'electrical') → Device

Creates a Van der Pauw (VDP) device with specified dimensions.

Parameters:

• diagonal (float) – Length of the VDP device, overall maximum dimension, in µm.

• contact_width (float) – Width of the contact points (width of the ports), in µm.

• layer (LayerSpec) – GDS layer specification

• port_type (string) – gdsfactory port type. default “electrical”

Returns:

(Device) – Van der Pauw cell

qnngds.test_structures.vernier_comb(pitch1: int | float = 0.5, pitch2: int | float = 0.1, layer1: LayerSpec = (1, 0), layer2: LayerSpec = (10, 0), text_angle: int | float = 0) → Device

Creates vernier caliper comb.

Helper method for alignment_mark.

Parameters:

• pitch1 (int or float) – pitch of top comb

• pitch2 (int or float) – pitch of bottom comb

• layer1 (LayerSpec) – center comb GDS layer specification

• layer2 (LayerSpec) – top/bottom comb GDS layer specification

• text_angle (int or float) – angle to rotate text labels

Returns:

(Device) – alignment vernier calipers

qnngds.test_structures.via_chain(via_spec: DeviceSpec | Device = <function via>, num_vias: int = 5, spacing: float = 10, tap_period: int = 1) → Device

Makes a chain of vias, with optional taps along the length of the chain.

Parameters:

• via_spec (DeviceSpec | Device) – function, component name, or component for the via

• num_vias (int) – number of vias to include in chain

• spacing (float) – spacing between vias

• tap_period (int) – number of vias between each tap. If zero, doesn’t place any taps.

Returns:

(Device) – the via chain

typing

Custom types for Layers and Devices

• LayerSpec: string, int, or tuple. int and tuple are pdk-agnostic, whereas string requires the a registered pdk to have a matching entry in its LayerSet.

• DeviceSpec: string, callable, Device. Like with LayerSpec, string requires a registered pdk with matching Device name

• CrossSectionSpec: string, callable, CrossSection. Like with LayerSpec, string requires a registered pdk with matching CrossSection.

utilities

Utilities for modifying/combining devices into more complex devices or constructing experiments.

qnngds.utilities.extend_ports(device: Device, port_names: Sequence[int | str], extension: DeviceSpec, auto_width: bool = False, new_ports: bool = True, ext_swap_ports: bool = False, ext_mirror: tuple[tuple[float, float], tuple[float, float]] | None = None) → Device

Adds the DeviceSpec extension to the named ports of Device device

Parameters:

• device (Device) – device to add extensions to

• port_names (Sequence[int | str]) – names of ports on device which should be extended

• extension (DeviceSpec) – specification for extension

• auto_width (bool) – if True, uses the kwarg start_width when instantiating the extension DeviceSpec to generate the tapers. Determines the start_width automatically from device.

• new_ports (bool) – if True, create new ports, using port 2 from Device specified by extension. Also passes any non-extended ports through to the new device that is returned.

• ext_swap_ports (bool) – if True, connects port 2 of the extension to the device instead of port 1.

• ext_mirror (tuple[tuple[float, float], tuple[float,float]] | None) – if not None, mirror the extension along the vector ext_mirror.

Returns:

(Device) – the original device with ports extended

qnngds.utilities.create_layered_ports(device: Device, layer: LayerSpec)

Regenerates new ports for device, assigning them all to a layer

Parameters:

• device (Device) – device to modify

• layer (LayerSpec) – GDS layer specification

qnngds.utilities.hyper_taper_fn(t: float, start_width: int | float, end_width: int | float) → float

Used for defining custom cross section widths/offsets

Parameters:

• t (float) – value on [0,1] mapping to position along length of taper

• start_width (float) – starting width (t=0)

• end_width (float) – ending width (t=1)

Returns:

(float) – hyper taper function evaluated at t.

qnngds.utilities.get_outline_layers(layer_set: LayerSet) → dict[str, float]

Get dictionary maping each layer in a LayerSet to its desired outline amount

Parameters:

layer_set (LayerSet) – LayerSet

Returns:

(dict[str, float]) – mapping of GDS layer name to outline distance. Layers that aren’t outlined are omitted.

qnngds.utilities.get_keepout_layers(layer_set: LayerSet) → dict[str, str]

Get dictionary maping a layer to a second layer which it should serve as a keepout for

Parameters:

layer_set (LayerSet) – LayerSet

Returns:

(dict[str, str]) – mapping of GDS layer name to GDS layer name.

qnngds.utilities.outline(device: Device, outline_layers: dict[str, float] | None = None, kl_tile_size: int | None = None, kl_precision: float = 0.0001) → Device

Outline polygons within device by layer.

Parameters:

• device (Device) – device to outline

• outline_layers (dict[str, float]) – map of desired outline amount per layer. If a layer is omitted, it will not be outlined

• kl_tile_size (int | None) – if not None, size of tile to divide geometry into for multithreaded execution

• kl_precision (int | None) – precision for KLayout operation (equivalently, sets dbu for KLayout)

Returns:

(Device) – the outlined device

qnngds.utilities.invert(device: Device, ext_bbox_distance: dict[LayerSpec, float] = {}, kl_tile_size: int | None = None, kl_precision: float = 0.0001) → Device

Outline polygons within device by layer.

Parameters:

• device (Device) – device to invert

• ext_bbox_distance (dict[LayerSpec, float]) – amount to expand bounding box for each layer. If a layer is omitted, it will not be inverted.

• kl_tile_size (int | None) – if not None, size of tile to divide geometry into for multithreaded execution

• kl_precision (int | None) – precision for KLayout operation (equivalently, sets dbu for KLayout)

Returns:

(Device) – the inverted device

qnngds.utilities.keepout(device: Device, outline_layers: dict[LayerSpec, float] | None = None, keepout_layers: dict[LayerSpec, LayerSpecs] | None = None, kl_tile_size: int | None = None, kl_precision: float = 0.0001) → Device

Apply keepout layers

Parameters:

• device (Device) – device to outline

• outline_layers (dict[LayerSpec, float]) – map of desired outline amount per layer. If a layer is omitted, it will not be outlined

• keepout_layers (dict[LayerSpec, LayerSpecs]) – map of desired layer(s) to keepout. If a keepout layer applies to a positive-tone layer (i.e. layer in outline_layers with non-zero outline), then the keepout regions will be unioned. If keepout layer applies to negative-tone (i.e. layer not in outline_layers), then the keepout region will be subtracted.

• kl_tile_size (int | None) – if not None, size of tile to divide geometry into for multithreaded execution

• kl_precision (int | None) – precision for KLayout operation (equivalently, sets dbu for KLayout)

Returns:

(Device) – device with keepout applied

qnngds.utilities.get_cross_section_with_layer(layer: LayerSpec = 'PHOTO1', default: CrossSectionSpec | None = None) → CrossSectionSpec | None

Find the cross section associated with the given layer, or default

Parameters:

• layer (LayerSpec) – layer specification to find cross section for

• default (CrossSectionSpec | None) – default return value if cross section is not found

Returns:

(CrossSectionSpec | None) – found cross section or default

qnngds.utilities.get_device_port_direction(component: Device) → dict[str, Sequence[Port]]

Returns ports of a component organized by direction.

Parameters:

component (Device) – component to get ports from

Returns:

(dict[str, Ports]) – list of ports for each direction