Dual-Wavelength Optical Parametric Oscillator Based on Birefringent Silicon Nitride Waveguide

Optical parametric oscillators (OPOs) are versatile and tunable light sources that are of great interest for spectroscopy and nonlinear microscopy [1], reaching wavelength ranges not accessible by typical laser gain media. OPOs offer a signal-idler pair whose wavelengths are tunable over a large bandwidth, however, not independently tunable to each other. By leveraging two independent amplification processes, dual-wavelength OPOs offer two independently tunable signal and idler pairs that can be tuned to arbitrarily small wavelength difference at any center wavelength [2]. Here, we demonstrate a dual-wavelength OPO based on a silicon nitride waveguide, exploiting four-wave mixing (FWM) in the two orthogonally polarized fundamental transverse modes of the waveguide to enable independent tuning of two idler pulses.