Stabilizing the free spectral range of a large ring laser

Abstract

A ring laser is defined by its perimeter, which directly enters the conversion factor between measured Sagnac frequency and the actual rotation rate. Large ring lasers employed in geodesy and fundamental physics require stability of the perimeter at or below the parts-per-billion level. We present two complementary approaches to actively control the perimeter length of such ring lasers, reaching a relative length stability of $4\times 10^{-10}$. One of these approaches is based on a phase detection between the beat of two resonances of different longitudinal mode index and a stable local oscillator. The other approach employs a highly stable wavelength meter to measure the absolute frequency of the laser light. These methods can readily be implemented and bring the stability of heterolithic devices on par with monolithic designs.

5 pages, 4 figures

References in corpus (6)

• Measuring Gravito-magnetic Effects by Multi Ring-Laser Gyroscope
• Analysis of ring laser gyroscopes including laser dynamics
• Passive, free-space laser gyroscope
• Compensation of the laser parameters fluctuations in large ring laser gyros: a Kalman filter approach
• A large scale passive laser gyroscope for Earth rotation sensing
• 3 m$\times$3 m heterolithic passive resonant gyroscope with cavity length stabilization

Cited by in corpus (2)

• Hänsch-Couillaud locking of a large Sagnac interferometer: advancing below the flicker floor
• Optical steering of a large ring laser