Quantum-enhanced laser phase noise filter

TL;DR

This paper demonstrates the first experimental quantum-enhanced laser phase noise filter using a noise ellipse rotation technique and squeezed vacuum injection, achieving up to 5 dB noise suppression across specific frequencies.

Contribution

It introduces a novel experimental setup combining noise ellipse rotation with amplitude noise suppression to enable quantum-enhanced phase noise filtering.

Findings

Achieved up to 5 dB phase noise suppression from 5 kHz to 60 kHz.

Demonstrated feasibility of using squeezed vacuum states for laser phase noise reduction.

Addressed primary limitations in phase noise extraction methods.

Abstract

Quantum noise is the fundamental limit of laser phase noise filter. We cannot realize the effective quantum-enhanced phase noise suppression through simply utilizing amplitude noise suppression scheme. Here, we present the first experimental demonstration of a quantum-enhanced laser phase noise filter, achieved by employing a noise ellipse rotation phase noise readout technique combined with an excess amplitude noise suppression scheme. We address the primary limitations in the extracting of laser phase noise, and make the quantum enhancement via squeezed vacuum injection feasible. A maximum of 5 dB quantum-enhanced phase noise suppression is realized across the Fourier frequencies from 5 kHz to 60 kHz. The demonstration unlocks the application of squeezed vacuum state in laser phase noise suppression.