Wide bandwidth phase-locked diode laser with an intra-cavity electro-optic modulator

TL;DR

This paper presents a novel wide bandwidth phase-locked diode laser system utilizing an intra-cavity electro-optic modulator, significantly reducing phase noise and enhancing stability for atom interferometry applications.

Contribution

The study introduces a new phase-locking scheme with an intra-cavity electro-optic modulator, achieving higher bandwidth and lower phase noise compared to traditional current feedback methods.

Findings

Phase-locked loop bandwidth ~10 MHz

Residual phase noise at -120 dBrad^2/Hz at 10 kHz

Reduced phase noise improves atom interferometer sensitivity

Abstract

Two extended cavity laser diodes are phase-locked, thanks to an intra-cavity electro-optical modulator. The phase-locked loop bandwidth is on the order of 10 MHz, which is about twice larger than when the feedback correction is applied on the laser current. The phase noise reaches -120 dBrad$^2$/Hz at 10 kHz. This new scheme reduces the residual laser phase noise, which constitutes one of the dominant contributions in the sensitivity limit of atom interferometers using two-photon transitions.