The basic working principle of fiber optic gyroscope

September 28, 2023

The resonant interference gyro uses a coherent light source, but the requirements for the coherent characteristics of the light source are greatly reduced, so that a general commercial DFB device can be used as a laser light source. The principle of the resonant interference gyro is shown in Figure 1. The transmission ring resonator structure is used in the figure, and the required output is obtained by mutual interference between the transmitted beams.

Miscellaneous, choose 2Lkβπ = as the bias to get the output curve of the resonant interference gyro in the passive case as shown in Figure 2. Compared with the reflective resonator cavity, the resonant cavity of the transmissive structure needs light to pass through two couplers in the resonator cavity, and there are losses on the coupler, so it is considered that the fineness of the output curve and the output amplitude are relatively small, but With the transmission structure, there is no coupler in the reflective resonator for spectroscopic detection of the detector, and the optical power utilization rate is 4 times that of the reflective resonator. The output curve of the resonant interferometric gyro is actually composed of two parts, 1) is the sum of the light intensity of the light transmitting part of the cavity transmitting toward each other; 2) is the mutual interference of the light transmitting parts of the two phases transmitting toward each other; The characteristics are the same as the output characteristics of the traditional resonant gyro. With the reduction of the coherence coefficient, the output light amplitude and fineness deteriorate rapidly, and the output fineness of the second part of the light is mainly determined by the system loss characteristics. Factors, so it is less affected by the coherence coefficient of the light source than the former.