Highly nondegenerate all-resonant optical parametric oscillator

We show that a nondegenerate multifrequency parametric oscillator has different properties compared with the usual three-wave parametric oscillator. We consider, as an example, a scheme for a resonant cw monolithic microwave-optical parametric oscillator based on high-Q whispering gallery modes excited in a nonlinear dielectric cavity. Such an oscillator may have an extremely low threshold and stable operation, and may be used in spectroscopy and metrology. The oscillator mimics devices based on resonant χ⁽³⁾ nonlinearity and can be utilized for efficient four-wave mixing and optical comb generation. Moreover, the oscillator properties are important to better understand the stability conditions of long-baseline interferometers with movable mirrors that are currently used for gravity wave detection.