Fiber-optical gyro used the principle of interference of Sagnac, make the laser as light source, light path of loop type is constructed by fiber, and inspect phase differences of two routes laser beam, the phase differences was caused by two beam (two beam from the pro and con hour hand was transmitted along optical fiber) rotated along with fiber loop, then will calculate the rate of angular speed of the optical gyroscope.

Fiber-optical gyro, its characteristic is that quickly start-up, extensive dynamic range, long life-span, good stability etc. it is suitable to be used in high precise measurement/ navigation system and servo system.