Ring laser gyroscope based on standard single-mode fiber and semiconductor optical amplifier

Abstract

In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The proposed optical gyroscope is a Ring Laser Gyroscope (RLG), in which the laser cavity is a fiber ring of standard single mode fiber where a semiconductor optical amplifier is used as the gain medium for the ring laser. Taking advantage of the bidirectional nature of the ring laser cavity, two counter-propagating waves are supported in the ring cavity. The two waves are identical in terms of their optical resonance frequency due to the reciprocity of the loop in the static position. A frequency shift is introduced between the two counter-propagating waves when the loop is subjected to an angular rotation, known as the Sagnac effect, and the magnitude of the shift is proportional to the rotation rate. Due to the multi-longitudinal mode nature of the constructed ring laser, the rotation sensor optical system parameters are optimized in a trade-off between the sensitivity and the dynamic range. Special signal processing algorithms are developed to enhance the RLG sensitivity. The performance of the RLG is evaluated using a rate table and the Allan variance of the sensor is extracted. The demonstrated RLG has an excellent linear scale factor with a dynamic range up to 40°/sec and a sensitivity down to 0.2°/sec. The RLG noise specifications as extracted from the Allan variance are a bias instability of 3°/h and an angular random walk of 0.5°/Vh.