Mid-infrared optical parametric oscillators based on uniform GaP waveguides.

Integrated chip-scale optical systems are an attractive platform for the implementation of non-linear optical interactions as they promise compact robust devices that operate reliably with lower power consumption compared to analogs based on bulk nonlinear crystals. The use of guided modes to facilitate nonlinear parametric interactions between optical fields, as opposed to bulk beams, has certain implications on optical parametric oscillations, the most important of which are additional methods for achieving phase synchronism and reduced threshold power due to the tight confinement associated with the guided modes. This work presents a theoretical investigation on the use of polarization dependent mode dispersion in guided wave structures as a means to achieve non-linear parametric oscillations from continuous wave sources with outputs in the mid-infrared region of the spectrum. An Al(2)O(3)/GaP/Al(2)O(3) waveguide system is investigated and shown to produce parametric oscillations at 3 µm to 5 µm from 1 µm to 2 µm input waves utilizing 0.14 µm to 0.30 µm GaP cores. The threshold power is shown to be 320 × less than that obtainable using more traditional quasi-phase matched bulk crystals over the same wavelength range.