Squeezing Enhancement Through Resonant Interference in Multi-ring Resonators

TL;DR

This paper presents a non-perturbative model for squeezed light generation in coupled microring resonators, demonstrating methods to suppress parasitic effects and enhance squeezing through resonant interference.

Contribution

It introduces a novel non-perturbative approach to analyze and optimize squeezing in multi-ring resonators, including techniques to suppress parasitic processes and improve output quality.

Findings

Near complete suppression of parasitic four-wave mixing with strong coupling

Significant enhancement of squeezing through hybridization-induced resonance shifting

Effective resonance splitting reduces thermal noise contributions

Abstract

We develop a non-perturbative description of squeezed light generation in an arbitrary lossy structure consisting of multiple coupled microring resonators. This is applied to two ring photonic molecules where the interference of the fields in the coupled rings leads to a modification in the resonance spectrum near a shared resonance. Considering a dual-pump degenerate squeezing scheme under a five resonance approximation, we investigate two methods to suppress parasitic four-wave mixing contributions and compensate for group velocity dispersion within a primary resonator through hybridization effects with a second auxiliary resonator. In the former case, this comes from an effective splitting of the unwanted resonances supporting parasitic four-wave mixing interactions that add thermal noise to the desired degenerate squeezed state. For sufficiently strong coupling between the resonators, we demonstrate near complete suppression of such parasitic processes, resulting in near unit fidelities with the corresponding output state that would arise were the parasitic interactions neglected. In the latter case, the hybridization effectively shifts a pump resonance, realigning the desired dual-pump four-wave mixing process and leading to a significant enhancement of the signal generation and output squeezing.