Widely separated optical Kerr parametric oscillation in AlN microrings

Here, we report χ⁽³⁾-based optical parametric oscillation (OPO) with widely separated signal-idler frequencies from crystalline aluminum nitride microrings pumped at 2 μm. By tailoring the width of the microring, OPO reaching toward the telecom and mid-infrared bands with a frequency separation of 64.2 THz is achieved. While dispersion engineering through changing the microring width is capable of shifting theOPOsideband by>9 THz, theOPO frequency can also be agilely tuned in the ranges of 1 and 0.1 THz, respectively, by shifting the pump wavelength and controlling the chip's temperature. At high pump powers, the OPO sidebands further evolve into localized frequency comb lines. Such large-frequency-shift OPO with flexible wavelength tunability will lead to enhanced chip-scale light sources.