Reentrant passive ring resonator fiber optic rotation sensor

Through theoretical and experimental studies of a novel reentrant FORS (RPR-FORS) which consists of a low-coherence length light source, a passive ring-resonator and a high performance reflector. A fiber optical rotation sensor (FORS) was developed with higher sensitivity and a shorter sensing loop. The sensitivity of RPR-FORS was analyzed as a function of the resonator coupler transmittance and the coupling ratio, the resonator transmittance and the reflector reflectivity. An experimental reflectivity curve for the reflector was obtained by mechanically changing the reflectivity, which illustrated the importance of the reflector in RPR-FORS. Experimental results showed that the phase modulator could be inserted inside the resonator or between the resonator and the reflector. but the two modulation methods had the same effect on RPR-FORS. The angular rate sensing signals were then obtained in the preliminary experiments. This RPR-FORS analysis provided a theoretical and experimental basis for the integrated optical rotation sensor.