High-sensitivity angular velocity measurement based on bidirectional coupled optoelectronic oscillator

Abstract

Optical gyroscopes play important roles in the field of angular velocity measurement. Improving the accuracy of the Sagnac effect is always an attractive research topic. In this work, a new scheme is proposed and demonstrated by using a polarization-maintaining bidirectional coupled optoelectronic oscillator (COEO) incorporating a Sagnac loop structure. In COEO resonant cavity, optical carrier and one of the first-order sidebands are separated by polarization delay interferometers, and propagate in opposite directions in the Sagnac loop. The rotation-induced phase difference between optical carrier and first-order sideband produces a frequency shift in COEO system. Moreover, for bidirectional system, the trends of resonant frequencies shift are opposite. Therefore, the difference of bidirectional resonant frequencies is the summation of unidirectional rotation-induced frequency shift. And less-complex, high-resolution microwave detection technology is used to improve the detection resolution of frequency difference. Therefore, a high-sensitivity angular velocity measurement system is implemented, with a sensitivity scale of 172.04 kHz/(rad/s). Theoretically, a minimally detectable angular velocity is 1.2 °/h.