Strong-coupling dynamics of frequency conversion in an optical microresonator

Nonlinear strong coupling in the frequency conversion process is an emerging field and has recently become accessible in integrated photonic platforms. Here we study the strong-coupling dynamics of second harmonic generation (SHG) in an optical microresonator. It is revealed that the nonlinear modal superposition, featuring intensity-dependent Rabi oscillation, leads to a clamped maximum SHG conversion efficiency, which can be broken through a self-injection configuration. Moreover, the nonlinear strong-coupling physics is revealed for various phenomena, including bistability, period-doubling bifurcation, and chaos. Additionally, pseudoHermitian degeneracy is found, where the synchronized resonances result in enhanced SHG efficiency. This work not only provides guidance for the implementation of high-efficiency photonic devices, but also may enrich the studies of nonlinear dynamics and non-Hermitian physics in optical microresonators.

Automated summary

This study investigates the nonlinear strong coupling dynamics of second harmonic generation in an optical microresonator, revealing phenomena such as intensity-dependent Rabi oscillation and clamped maximum SHG conversion efficiency. Additionally, multiple nonlinear strong coupling physics phenomena are observed, including bistability, period-doubling bifurcation, and chaos. The study also identifies pseudoHermitian degeneracy, which enhances SHG efficiency through synchronized resonances. This work is important for the implementation of high-efficiency photonic devices and enriching the understanding of nonlinear dynamics and non-Hermitian physics in optical microresonators.