A naturally stable Sagnac-Michelson nonlinear interferometer

TL;DR

This paper introduces a stable, simplified nonlinear interferometer using a single parametric amplifier, achieving high visibility and noise reduction without active stabilization, advancing practical sensor development.

Contribution

It presents a novel, stable nonlinear interferometer design with fewer components and no active stabilization, enhancing practical sensing applications.

Findings

Achieved up to 99.9% interference visibility

Demonstrated noise reduction via phase-sensitive gain

Requires fewer components than previous designs

Abstract

Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing---conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9\% interference visibility and find evidence for noise reduction based on phase-sensitive gain. Our configuration utilizes fewer components than previous demonstrations and requires no active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.