Realization of Hollow-Core Photonic-Crystal Fiber Optic Gyro Based on Low-Noise Multi-Frequency Lasers with Intermediate-Frequency Difference. - Hongchen Jiao; Lishuang Feng; Qingjun Zhang; Jie Liu; Tao Wang; Ning Liu; Chunqi Zhang; Xindong Cui; Xiaoning Ji (Sensors, 2020)