Effects of back reflection on the fiber ring laser gyroscope

In this Letter, the effects of the backreflection coefficient on a fiber ring laser gyroscope (FRLG) are discussed in detail. By applying the mode coupling equations, the eigenmodes in the FRLG are theoretically analyzed. We have found that the degree of intensity oscillation is intimately related to the backreflection coefficient in the FRLG; we have also explored the theoretical responding curve of FRLG. By utilizing a bidirectional filter with a tunable back-reflection coefficient, our conclusions are proven. Two responding curves were obtained under two different back-reflection coefficients, the scale factors of which are 1.4405 kHz/ deg ·s^-1 and 1.3096 kHz/ deg ·s^-1, respectively. The lock-in ranges of the curves are within 10 deg/s and 15 deg/s.