Abstract: Fiber-optic gyroscope is a new kind of inertial device.It has the highest theoretic sensitivity.But at present,its actual sensitivity is far less than the theoretic sensitivity.The main cause is:there are Rayleigh scattering,birefringence phenomenon and other nonlinear effects,such as Kerr effect,in optical fibers.They will cause nonreciprocal phase shifts of beams.This paper proposes to compensate such nonreciprocal phase errors by using photorefractive crystal,a new kind of nonlinear optical material,that is,using its thermal lens effect to weaken or eliminate the influence of Rayleigh scattering,using its bilateral phase effect to eliminate or correct the influence of birefringence phenomenon and Kerr effect,and then to improve the sensitivity of fiber-optic gyroscope.

Key words: fiber-optic gyroscope； sensitivity； photorefractive crystal； photorefractive effects；