Racetrack Resonator
A racetrack resonator is a closed loop waveguide with a coupling waveguide, separate by a small gap. The resonator acts as a cavity with resonant behaviour at specific wavelengths. SiFab contains two types of racetrack resonators:
RacetrackResonator: a racetrack defined by the coupling length, bend radius and total length.
RacetrackResonatorFSR: a racetrack defined by the coupling length, bend radius and free spectral range.
RacetrackResonator
This is a parametric racetrack resonator. You specify the bend radius and coupling length, and by default a ring resonator will be returned. You can also specify the total length of the resonator. If you do this, vertical waveguide sections will be added to increase the length without affecting the bend radius or coupling length.
Reference
Click on the name of the component below to see the complete PCell reference.
Racetrack resonator based on the coupling gap and ring radius. |
Example
from si_fab import all as pdk
racetrack = pdk.RacetrackResonator(
gap=0.75,
length=200,
coupling_length=25,
radius=20,
)
racetrack_lv = racetrack.Layout()
racetrack_lv.visualize(annotate=True)
RacetrackResonatorFSR
This behaves similarly to the RacetrackResonator, but instead of passing in a length, we pass in a Free Spectra Range (FSR). It then uses the group index of the trace template to define the length of the resonator. The units of FSR are in nanometers, and is 1 nm by default.
Reference
Click on the name of the component below to see the complete PCell reference.
Racetrack resonator with radius defined by a desired Free Spectral Range (FSR). |
Example
from si_fab import all as pdk
racetrack = pdk.RacetrackResonator(
gap=0.75,
length=200,
coupling_length=25,
radius=20,
)
racetrack_lv = racetrack.Layout()
racetrack_lv.visualize(annotate=True)