Soliton Generation in a Gallium Phosphide Photonic Crystal Cavity

Microring resonators, particularly those made of silicon nitride (Si 3 N 4 , have become the most common platform for dissipative Kerr soliton formation [1]. However, ring resonators do not offer many degrees of freedom; usually only waveguide thickness and width can be varied. Photonic-crystal Fabry-Pérot (PC-FP) resonators offer more prospects for dispersion engineering due to the multiple degrees of freedom available in the design of the photonic crystal reflectors (PCR) and, in turn, the evolution of the photonic bandgap within the distributed reflector [2]. For such devices, gallium phosphide (GaP) represents an intriguing material because of its high refractive index $(\mathrm{n}_{0} > 3)$ , relatively high third-order nonlinearity, nonzero second-order nonlinearity, negligible two-photon absorption for wavelengths above 1.1 $\mu \mathrm{m}$ , and recently developed nanofabrication processes [3].