Extended Data Fig. 1: Tunability of pump frequency and turning on-off using the heater.
From: High-efficiency and broadband on-chip electro-optic frequency comb generators
Spectra of the device pumped at 1530 nm (purple trace) and 1603 nm (blue trace and red trace). By tuning the resonances of cavity 1 to match the resonances of cavity 2, the device can be pumped at different wavelengths. The cut-off at wavelengths that are far blue-detuned (purple trace) is due to TE-TM (transverse electric-transverse magnetic) polarization crossing, which affects the TE-designed cavity 2, and can be minimized by additional dispersion engineering35. The comb can also be turned off simply by tuning the resonance of cavity 1 to be mis-aligned from cavity 2. The blue and red traces show the on and off comb states by changing the heater voltages without changing the laser or microwave drive, showing an excellent extinction ratio.
