Analysis of Acousto-Optic Errors in Laser Gyroscopes.

摘要

Acousto-optic modulators frequency shift and spatially orient the laser beam within the laser gyroscope cavity. The accuracy of the gyroscope is directly related to the modulator performance. This study investigates two commercial styles of modulators and their impact on gyroscope operation. The drive frequency of the modulators was varied to measure the angular shifts of the first order diffracted beam. The angular deflections concurred with manufacturer specifications with a maximum mean difference of -0.1869 milliradians and maximum standard deviation of 0.2005 milliradians. Using these angular values, the reflectivities of the flat mirrors within the cavity were then determined. These calculations displayed an average reflectivity of .999567 with most changes occurring in the seventh decimal place, indicating that properly aligned modulators do not affect mirror reflectivity or gyroscope finesse.