Dissipative quadratic solitons: few-cycle frequency combs in the mid-IR

Abstract

A plethora of applications have recently motivated extensive efforts on the generation of low noise Kerr solitons and coherent frequency combs in various platforms ranging from fiber to whispering gallery and integrated microscale resonators. However, the Kerr (cubic) nonlinearity is inherently weak, and in contrast, strong quadratic nonlinearity in optical resonators is expected to provide an alternative means for soliton formation with promising potential. In this talk we overview recent experimental results on formation of two types of dissipative quadratic solitons in optical parametric oscillators, namely temporal simultons in the mid-infrared and temporal walk-off induced solitons. Unlike Kerr solitons, these quadratic solitons occur in low-finesse resonators and can provide substantial pulse compression and high conversion efficiencies. We present a route to significantly improve the performance of these demonstrated quadratic solitons when extended to an integrated platform.