Highly stable modular-assembled laser system for a dual-atom-interferometer gyroscope

TL;DR

This paper presents a compact, thermally stable fiber laser system with all-quartz modules designed for a dual-atom-interferometer gyroscope, demonstrating high stability and suitability for field applications.

Contribution

It introduces a novel modular fiber laser system with enhanced thermal stability and stability metrics, suitable for portable atom-interferometer gyroscopes.

Findings

Laser power fluctuation below 0.1% at room temperature

Polarization extinction ratio over 30 dB

Frequency fluctuation under 91 kHz

Abstract

Operating atom-interferometer gyroscopes outside a laboratory environment is challenging primarily owing to the instability of laser systems. To enhance the thermal stability of free-space laser systems, a compact laser system using fiber lasers and all-quartz-jointed optical modules was developed for a dual-atom-interferometer gyroscope. Millimeter-scale optical elements jointed on quartz plates with identical quartz supports, ensure laser power stability and facilitate component upgrades. The primary diode laser was locked to the modulation transfer spectrum of Rb atoms, and Raman lasers were phase-locked to the primary laser. Frequencies for repumping, blow-away, and detection lasers were adjusted with acousto-optic modulators. At room temperature, laser power fluctuation was under 1:1000, polarization extinction ratio exceeded 30 dB, frequency fluctuation was below 91 kHz, and phase noise reached to -100 dBc/Hz @ 1 kHz. The optical modules were tested at 5--50 $^{\circ}$C and applied to a dual-atom-interferometer gyroscope. The fringe contrast was tested over the temperature range. The proposed system paves the way for promoting field applications of atom-interferometer sensors.