The Caltech Holisitic Integrated Circuits KLayout Photonic Element Autogenerator (chickpea) is a python package that can be imported into a python-based KLayout macro from which functions can be called that will generate various photonic devices. The value of the package lies in that functional parameters of the device are passed to the generating function, and the generating function produces the device layout.
This package needs a version of KLayout that has numpy built in. Versions 0.25 and 0.26 have both been verified to work with chickpea.
Clone the chickpea directory into the directory
C:\Users\[user name]\AppData\Roaming\KLayout\python
The name 'chickpea' can then be used to import the python package into any python-based KLayout macro.
- N-to-N parallel port auto-routing
- Delay spirals
- Directional Couplers
- Parabolic and linear tapers
- S-bends
Here is an example script that generates a directional coupler. Note the import statements at the top of the file using this folder name. There, we import a sub-module (corresponding to .py files inside the folder) called 'couplers', which includes the function we want to generate a directional coupler with.
# This script generates a directional coupler.
import pya # Module containing KLayout API
from chickpea import couplers # contains directional coupler generation
from chickpea import paths # path/waveguide generation
layout = pya.Layout() # create new layout
top = layout.create_cell("TOP") # create top-level cell
dc = layout.create_cell("dc") # create cell for a dir'nal coupler
rib = layout.layer(1, 0) # create rib waveguide layer
couplers.dir_coupler(layout, rib,
dc, # place the entire coupler in the cell 'dc'
10, # set the coupling length to 10 um
20, # make all s-bend arm lengths 20 um
10, # make all s-bend arm heights 10 um
sbend_output='pcell' # Have the s-bends output as PCells
)
# Insert the cell 'dc', which contains the directional coupler,
# into the top cell of our layout.
top.insert(pya.DCellInstArray(
dc.cell_index(),
pya.DTrans(pya.DVector(-20, 70)) # Shift away from first coupler
))
# Write the layout to a GDS file at this path
layout.write("C:/Users/julli/Desktop/dir_coupler.gds")-
There's a subdirectory within chickpea called "example_scripts", which contains example KLayout macro scripts using the functions provided by chickpea, along with the GDS files that each of those macros generate.
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At the top of the .py files in the package, there is a list of "top level functions" that briefly list and describe the functions in that file that might be used in a macro script (as opposed to the helper functions in that file, which are only used within the chickpea package). From those names, you can either ctrl+F the files or use python's help() function to read the function docstrings for detailed reference documentation on each function. This may contain details the example scripts don't.
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There is also a subdirectory called "user_manual". Right now, it just contains some examples of the outputs of various parameter sets supplied to the delay spiral function, and in the future may contain information on the geometry involved in the package's various functions.
- DLL load failed: The specified module could not be found. If KLayout gives this message when attempting to run a macro that uses chickpea, followed by messages indicating it can't find numpy, close KLayout and open it via the start menu/taskbar/equivalent, NOT by double clicking on a GDS file. It KLayout is opened the latter way, it seems it won't load numpy properly. Bug present in KLayout v. 0.26
This is the first public release of chickpea. The major features follow:
- N-to-N parallel port auto-routing
- Delay spirals
- Directional Couplers
- Parabolic and linear tapers
- S-bends