Soliton linear-wave scattering in a Kerr microresonator

The nonlinear scattering of a linear optical wave from a conservative soliton has been widely studied in optical fibers as a mechanism for nonlinear frequency conversion. Here we extend this analysis to consider the scattering of an externally injected probe wave from a dissipative cavity soliton circulating in a Kerr microresonator. We demonstrate, both theoretically and experimentally, that this nonlinear interaction can be harnessed for useful expansion of the soliton frequency comb via the formation of a secondary idler comb. We explore the physics of the process, showing that the phase detuning of the injected probe from a cavity resonance plays a key role in setting the central frequency of the idler comb, thus providing a convenient parameter through which to control the spectral envelope of that comb. Our results elucidate the dynamics that govern the interactions between dissipative Kerr cavity solitons and externally injected probe waves, and could prove useful in the design of future Kerr frequency comb systems by enabling the possibility to provide high-power comb lines in a specified spectral region simply through the injection of a suitably chosen probe. Tuneable microresonator frequency combs offer low-power, coherent light with a small device footprint. Here, the concept of controlling the comb frequency by detuning the probe phase is translated from photonic crystal fibres to a Kerr microresonator.

Automated summary

This paper investigates the scattering of an externally injected probe wave from a dissipative cavity soliton in a Kerr microresonator, and demonstrates the potential of using this nonlinear interaction to expand the soliton frequency comb. The research shows that the detuning of the injected probe from a cavity resonance plays a key role in controlling the central frequency and spectral envelope of the comb.