Precision stabilization of the optical frequency in a large ring laser gyroscope

Abstract

Pressure-induced fractional changes of 10(-7) in the geometry of a large He-Ne ring laser gyroscope induce backscatter phase changes and thus a fractional pulling of the Sagnac frequency of ~5 x 10(-3). To counter this, the optical frequency was stabilized against an iodine-stabilized laser with a high-finesse Fabry-Perot interferometer and piezoelectric control of the ring perimeter. This scheme, although limited in principle by residual geometric asymmetry and in practice by low beam powers (10 pW), stabilized the perimeter to 2.4 nm (6 x 10(-10) or 300 kHz for the optical frequency) and the Sagnac frequency to 100 parts per million over several days.

A 1.82 m2 ring laser gyroscope for nano-rotational motion sensing

“…As already observed in [17] and [18], this operation solves the problem of the discontinuous operation regime characterized by split-mode transitions, but introduces a slow modulation in the value of the Sagnac frequency that results to be proportional to the temperature drift rate of the gyrolaser structure. This can be explained by considering that moving a single mirror along the cavity diagonal changes the length of the two adjacent sides, while the two opposite side are, at first order, unchanged.…”

Earth tide and tilt detection by a ring laser gyroscope

“…Since the amplitude of these periodic cavity length variations of 4 nm is so small, variations of the scaling factor (4 A )/(λ P ) can be excluded as a cause. Frequency pulling by backscatter phase variations [ Schreiber et al , 1998], however, may well generate such a response of periodic Sagnac frequency variations.…”

“…Perimeter stabilization was then abandoned and the optical geometry and mirror mounting were fully symmetrized (in December 1998). It was expected that with a free‐floating but symmetrical ring, the relative phase of backscattered beams would remain constant to first order under pressure and temperature variations since (apart from mode jumps) the optical wavelength would scale in proportion to all the mirror separations [ Schreiber et al , 1998]. Indeed a dramatic reduction in drift was obtained [ Schreiber et al , 1999].…”

Reflectance and transmittance model for multilayer optical coatings with roughness at oblique incidence

“…However, actually any thin film has certain surface roughness. In some applications, this roughness has a very important influence on its optical characteristics, such as deep-ultraviolet sculpture [1], ring lasers [2], gravitational wave detectors [3], etc. Therefore, it is important to establish a theoretical analysis model of multilayer optical characteristics when considering surface roughness.…”