Dark Pulse Formation in an Integrated Optical Parametric Oscillator

There is a growing demand to reduce the footprint of frequency comb sources to enable their large-scale deployment. The formation of Kerr cavity solitons (CSs), relying on cubic nonlinear effects, currently dominates the landscape of integrated frequency comb formation [1]. Interestingly, second-order nonlinear resonators such as degenerate optical parametric oscillators (DOPOs) are known to support temporal soliton [2]–[3]. These quadratic CSs offer three main advantages over their cubic counterparts: (i) reduced requirements on pump power and/or resonator Q, (ii) no constraint on the dispersion regime, and (iii) the generation of OFCs in spectral regions that are otherwise hard to access. Despite these potentials, experimental demonstrations of purely quadratic CSs have been limited to Turing rolls [4], simultons [5], or walk-off solitons [6].