Parametrically driven Kerr cavity solitons

Cavity solitons are optical pulses that propagate indefinitely in nonlinear resonators. They are attracting attention, both for their many potential applications and their connection to other fields of science. Cavity solitons differ from laser dissipative solitons in that they are coherently driven. So far the focus has been on driving Kerr solitons externally, at their carrier frequency, in which case a single stable localized solution exists for fixed parameters. Here we experimentally demonstrate Kerr cavity solitons driving at twice their carrier frequency, using an all-fibre optical parametric oscillator. In that configuration, called parametric driving, two backgroundless solitons of opposite phase may coexist. We harness this multiplicity to generate a string of random bits, thereby extending the pool of applications of Kerr cavity solitons to random number generators and Ising machines. Our results are in excellent agreement with a seminal amplitude equation, highlighting connections to hydrodynamic and mechanical systems, among others. Parametric driving of Kerr solitons – cavity soliton excitation around twice the carrier frequency of solitons – in an optical parametric oscillator with competing nonlinearities look prone to extend the applications of Kerr resonators to random number generators and Ising machines.