Widely tunable dual-wavelength waveguide-based optical parametric oscillator

We present a widely tunable dual-wavelength optical parametric oscillator (OPO), exploiting degenerate four-wave mixing within both fundamental transverse modes of a single silicon nitride waveguide within a single cavity. Independent dispersive tuning of two idler outputs was realized through a tunable birefringence within the cavity. Benefiting from the broadband four-wave mixing gain of the fundamental TE and TM modes in the waveguide, as well as from the orthogonally polarized and delayed pumping scheme, the OPO, pumped with a fiber laser at 1.03 µm wavelength, generated two independently tunable idler pulses with arbitrary frequency spacing ranging from zero up to 65 THz in the wavelength region from 1.11 to 1.46 µm. This believed to be novel dual-wavelength waveguide-based OPO paves the way toward various multi-wavelength applications.