Manual workflow tutorial

In this step-by-step example, we show how to use an existing chip in the KLayout GUI, and manually modify the elements on the chip.

Note

This workflow results in a static geometry, which no longer corresponds to the python code that defined the original chip. In the section Getting started we will show how to create chips in python code.

This manual workflow can be also used as a starting point for a new chip. See Converting elements placed in GUI into code to learn how to generate python code from the static chip.

Generate Demo chip

  1. Open KLayout in editing mode (see Usage)

  2. In the Libraries panel on the bottom left, choose Chip Library and drag and drop the Demo chip from there to the layout.

  3. Click Ok in the PCell parameters window that opens.

Convert the chip cell to static

We now have a parametrized chip cell placed in the layout. We can change the parameters of the chip, but not manually edit the elements and geometry inside the chip. To edit the elements manually, we convert it to a static cell:

  1. Locate Cells panel on the left.

  2. Left click on the cell named ChipLibrary.Demo to select it.

  3. In the top menu, navigate to Edit->Cell->Convert to Static Cell.

  4. In the Cells panel, right click on the cell named Demo$1.

  5. From the drop down menu, select Show as new top.

Note that this is a one-way process, a static cell cannot be converted back to a PCell.

The elements inside the Demo$ cell, such as qubits and waveguides, are still PCells, and we will change their parameters to modify the geometry in the following steps.

Change the shape of a waveguide

Waveguides follow a path of nodes, which can be edited with the Partial tool

  1. In the Layout panel locate a charge line of the qubit. It connects the top left launcher and the qubit.

  2. Click once on the charge line to select it.

  3. Press Shift+F2 to zoom in.

  4. From the Tools panel above the Layout panel select a tool Partial.

  5. Double click on the center of the charge line. A new node should appear there.

  6. Drag the new node with the mouse. The waveguide should change shape.

See Using waveguides for more details.

Change the location of an element

Elements can be moved with the Move tool. For example, to move a qubit:

  1. Press F2 to see the whole top cell.

  2. Locate the qubit in the top left part of the chip.

  3. Drag a selection box around the qubit.

  4. From the Tools panel select Move.

  5. Click on the selection box.

  6. Click on a new location for a qubit.

Modify element parameters

The parameters of each element can be modified as follows:

  1. From the Tools panel select Select.

  2. Drag a selection box around the qubit.

  3. Click Shift+F2

  4. Press q.

  5. In the new Instance Properties window locate a tab PCell parameters.

  6. Scroll down in the list of parameters to locate Coupler lengths.

  7. Change the value in the text box to 100,160,0.

  8. Click Ok.

Add new elements

Here, we add a new qubit.

  1. Press F2 to see the whole top cell.

  2. From the toolbar select Instance.

  3. In the new Editor Options window locate Library.

  4. Using the drop-down menu select Qubit Library.

  5. Click on a button 🔍 a little bit to the left from the Library for older versions click ... a little bit to the left from the. Library.

  6. From the new Select Cell window select Swissmon and press Ok.

  7. In the Object Edit or Options window press Ok.

  8. Click at the location of the new qubits.

  9. Click Esc to finish placing qubits.

Adding ground grid

KQCircuits can generate a standard flux pinning grid on all ground plane areas. If you plan to convert the layout to python code, you can skip this step - in that case the ground grid can be added during mask export.

If you want to use the static layout for fabrication, you can add the ground grid as follows. Do this as the very last step.

  1. In the top menu, navigate to KQCircuits -> Fill with ground plane grid. It may take some time to generate. Unhide ground grid in layers list located in the top right.