Self-Injection Locking and Phase-Locked States in Microresonator-Based Optical Frequency Combs

TL;DR

This paper investigates phase locking phenomena in microresonator-based optical frequency combs, revealing experimental insights into their transition to stable states and the coexistence of phase stability with non-deterministic phase relationships.

Contribution

It provides experimental evidence of injection locking and phase-locked states in microcombs, addressing gaps in existing theoretical models.

Findings

Demonstrated phase-locked states with injection locking characteristics.

Observed phase-stable combs with non-deterministic phase relationships.

Provided experimental insights into comb transition mechanisms.

Abstract

Microresonator-based optical frequency combs have been a topic of extensive research during the last few years. Several theoretical models for the comb generation have been proposed; however, they do not comprehensively address experimental results that show a variety of independent comb generation mechanisms. Here, we present frequency-domain experiments that illuminate the transition of microcombs into phase-locked states, which show characteristics of injection locking between ensembles of comb modes. In addition, we demonstrate the existence of equidistant optical frequency combs that are phase stable but with non-deterministic phase relationships between individual comb modes.