Directional amplifier in an optomechanical system with optical gain

TL;DR

This paper proposes a novel optomechanical scheme for a directional amplifier that utilizes optical gain and phase control to achieve nonreciprocal signal amplification between optical and microwave fields with suppressed noise.

Contribution

It introduces a new optomechanical configuration with optical gain for controllable directional amplification and noise suppression, advancing nonreciprocal device design.

Findings

Achieves optical directional amplification with phase-controlled directionality.

Demonstrates noise suppression in the large cooperativity limit.

Identifies conditions for maximum gain and effective nonreciprocity.

Abstract

Directional amplifiers are crucial nonreciprocal devices in both classical and quantum information processing. Here we propose a scheme for realizing a directional amplifier between optical and microwave fields based on an optomechanical system with optical gain, where an active optical cavity and two passive microwave cavities are, respectively, coupled to a common mechanical resonator via radiation pressure. The two passive cavities are coupled via hopping interaction to facilitate the directional amplification between the active and passive cavities. We obtain the condition of achieving optical directional amplification and find that the direction of amplification can be controlled by the phase differences between the effective optomechanical couplings. The effects of the gain rate of the active cavity and the effective coupling strengths on the maximum gain of the amplifier are discussed. We show that the noise added to this amplifier can be greatly suppressed in the large cooperativity limit.