Fiber gyroscope using a depolarizing single-mode optical fiber

An optical-fiber gyroscope having strong depolarization and birefringence is described. The device consists of several of discrete elements, including: a semiconductor laser; two beams splitters; a photodetector; and a synchronous detector. The main operating principle of the gyroscope is stabilization of the output signal from the semiconductor laser by means of coiled, depolarizing optical-fiber. The birefringence of a short length of the optical fiber is delta n = 0.00003, where delta n is the difference between the effective refractive indices of the two orthogonally polarized modes. In recent experiments with a prototype gyroscope system, a sensitivity of about 0.2 deg/hr was obtained. The long term stability was about 1 deg/hr. A block diagram of the prototype gyroscope system is provided.