KQCircuits is a Python library developed by IQM for automating the design of superconducting quantum circuits. It uses the KLayout layout design program API.

KQCircuits generates multi-layer 2-dimensional-geometry representing common structures in quantum processing units (QPU). It includes definitions of parametrized geometrical objects or “elements”, framework to easily define your own elements, framework to get geometry from the elements by setting values to parameters and a framework to assemble a full QPU design by combining many of the elements in different geometrical relations. Among other templates, are also structures to combine QPU designs to create optical mask layout and EBL patterns for fabrication of quantum circuits and export a set of files for a mask as needed for QPU fabrication.

KQCircuits is a KLayout extension. KLayout can be used either using a graphical user interface or as a standalone python module. For the first time users, the graphical user interface (GUI) mode is recommended.

Video tutorials for the GUI installation can be found on YouTube.

Windows	Ubuntu	MacOS

First install KLayout. Afterwards you can install KQCircuits as a plug-in to use KQCircuits features within your KLayout GUI editor session.

To quickly try out KQCircuits GUI features we recommend installing the Salt package of KQCircuits inside your KLayout application. The Salt package is easier to install and get started, but the built-in elements cannot be modified. See Salt installation guide here.

The developer setup is recommended for advanced users who want to modify KQCircuits code and to contribute to the project.

After installing KLayout run:

python setup_within_klayout.py

For further details see the developer setup documentation.

Installing KQCircuits as a standalone python module allows you to use KQCircuits features in your own python code with:

import kqcircuits

You will also get access to kqc related terminal commands such as:

kqc mask quick_demo.py              # To build a wafer mask, in this case quick_demo.py
kqc sim waveguides_sim_compare.py   # To export and run waveguide simulation

For standalone installation run command

python -m pip install -e "klayout_package/python[docs,tests,sim]"

For improved security you can also validate the fetched dependencies of KQCircuits. Further details available in the documentation.

Documentation for KQCircuits can be found here.

It may also be generated from the sources with make html in the docs directory.

Follow the User Guide for tutorials.

KQC currently supports exporting to Ansys HFSS/Q3D (also with pyEPR), Sonnet, and Elmer.

Parameter sweeps are easy to implement, for example

simulations = sweep_simulation(layout, sim_class, sim_parameters, {
    'cpl_length': [160, 180, 200],
    'arm_width': [24, 28, 32, 36],
})

exports simulations with the given individual parameters varied roughly as in the animation.

A sweep of all possible combinations between the given parameters is done by changing the function to cross_sweep_simulation. Check klayout_package/python/scripts/simulations for example simulation exports.

If you have any questions, problems or ideas related to KQCircuits, please start a discussion in GitHub or create a GitHub issue.

Contributions to KQC are welcome from the community. Contributors are expected to accept IQM Individual Contributor License Agreement by filling a form at IQM website. See also section Contributing in the documentation.

Please see the documentation for instructions on how to cite KQCircuits in your projects and publications.

This code is part of KQCircuits

Copyright (C) 2021-2024 IQM Finland Oy

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/gpl-3.0.html.

The software distribution should follow IQM trademark policy for open-source software (meetiqm.com/iqm-open-source-trademark-policy). IQM welcomes contributions to the code. Please see our contribution agreements for individuals (meetiqm.com/iqm-individual-contributor-license-agreement) and organizations (meetiqm.com/iqm-organization-contributor-license-agreement).

KQCircuits is a registered trademark of IQM. Please see IQM open source software trademark policy.