Output optics detection system

TLDR: In this paper, a ring laser gyroscope output optics detection system, including a rotational sensing system and cavity length control system for a multioscillator ring LYG, is presented.

Abstract: A ring laser gyroscope output optics detection system, including a rotational sensing system and cavity length control system for a multioscillator ring laser gyroscope, is disclosed herein that can operate with a simple upright symmetric optics mechanism, where the reguired signal separation is performed fully electronically. In a preferred embodiment, signal separation circuitry is provided which performs a 90° or .pi./2 radians phase shift to one of a set of heterodyned signals in order to extract the Sagnac effect modulated Faraday frequency signals WA and WB. In order to deal with the inherent problems of crosstalk present in a Faraday biased system, alternative signal separation schemes suggest the use of a 45° or .pi./4 radians phase shift, as well as a 60° or .pi./3 radians phase shift. Complementary cavity length control schemes are presented in both fixed component and digitally controlled formats.