Phase Steps and Hot Resonator Detuning in Microresonator Frequency Combs

TL;DR

This paper advances understanding of Kerr-effect microresonator frequency combs by measuring phase, amplitude, and detuning of comb modes, revealing novel phase step phenomena in comb states.

Contribution

It introduces a method to measure resonator dispersion and mode detuning during comb generation, uncovering unexpected phase step behaviors.

Findings

Discovered discrete π and π/2 phase steps in comb states

Developed a technique for in-situ measurement of mode detuning

Revealed complex phase dynamics not seen in traditional combs

Abstract

Experiments and theoretical modeling yielded significant progress towards understanding of Kerr-effect induced optical frequency comb generation in microresonators. However, the simultaneous interaction of hundreds or thousands of optical comb frequencies with the same number of resonator modes leads to complicated nonlinear dynamics that are far from fully understood. An important prerequisite for modeling the comb formation process is the knowledge of phase and amplitude of the comb modes as well as the detuning from their respective microresonator modes. Here, we present comprehensive measurements that fully characterize optical microcomb states. We introduce a way of measuring resonator dispersion and detuning of comb modes in a hot resonator while generating an optical frequency comb. The presented phase measurements show unpredicted comb states with discrete {\pi} and {\pi}/2 steps in the comb phases that are not observed in conventional optical frequency combs.