Degenerate squeezing in a dual-pumped integrated microresonator: parasitic processes and their suppression

TL;DR

This paper theoretically analyzes how parasitic nonlinear processes affect degenerate quadrature squeezing in dual-pumped integrated microresonators and proposes pump detuning as a method to suppress these effects, enhancing squeezing quality.

Contribution

It introduces a Hamiltonian-based model considering multiple resonance modes to study parasitic processes and demonstrates how symmetric pump detuning can mitigate these effects in integrated microresonators.

Findings

Symmetric pump detuning reduces parasitic nonlinear effects.

Enhanced squeezing quality achieved without structural changes.

Higher pump power needed for target squeezing levels.

Abstract

Using a general Hamiltonian treatment, we theoretically study the generation of degenerate quadrature squeezing in a dual-pumped integrated microring resonator coupled to a waveguide. Considering a dual-pump four-wave mixing configuration in an integrated $\text{Si}_3\text{N}_4$ platform, and following the coupled-mode theory approach, we investigate the effects of parasitic quantum nonlinear optical processes on the generation of squeezed light. Considering five resonance modes in this approach allows us to include the most important four-wave mixing processes involved in such a configuration. We theoretically explore the effects of the pump detunings on different nonlinear processes and show that the effects of some of the parasitic processes are effectively neutralized by symmetrically detuning the two pumps. This yields a significant enhancement in the output squeezing quality without physically changing the structure, but suffers from the trade-off of requiring substantially higher pump power for a fixed target level of squeezing.