Vibration-insensitive optical path length control transducer for ring laser gyroscope

Abstract

A ring laser gyroscope is an optical sensor based on the Sagnac effect. It has many outstanding advantages, such as a short start-up time, a high precision, a wide dynamic range and a stable scale factor. It is insensitive to accelerations and is in wide use in aircraft attitude control, north finding applications including navigation and space missions. The path length transducer in a ring laser gyroscope is required to stabilize the optical path of the laser beams in the cavity. The path length control transducer may tilt in complex environment, which will cause deformation of resonant optical path in resonant cavity and seriously influence the performance of ring laser gyroscope. Firstly, for the first time, finite element analysis software ANSYS was used to simulate and analyze the small deformation of ring laser gyroscope’s grooved mirror in three directions under typical random vibrational spectra, their value were 2.08 $"$ , 2.10 $"$ and 1.30 $"$ respectively, and the deformation in the diaphragm of resonant cavity was obtained by combining with matrix optical theory quantitatively. Secondly, the influence rule of different radius of curvature and isostructural parameters on the tilt of path length control transducer was sought through quantitative analysis. Finally, combining with the change law of axial displacement in literature [5], an evaluation criterion for optimization was given and the optimized parameters were listed for path length control transducer. The tilt was reduced to 0.33 $"$ after optimization, which was about 21.4% of current structure. The axial displacement reached 3.89 um, which was 1.84 times of existing structure. The research in the paper could provide reference for the design of path length control transducer of ring laser gyroscope.