Fiber-optic laser gyro with easily introduced phase-difference bias

Drift reduction in an optical heterodyne fiber gyro

An optical heterodyne fiber gyro, which we recently proposed, is improved to reduce the zero-point drift. A reference interferometer is introduced in the improved configuration beside the sensing interferometer to obtain the Sagnac phase shift, which monitors the drift caused in the optical system. Experimental results demonstrate successful reduction of the drift.

Synchronously pumped fiber Raman gyroscope

A new optical gyroscope has been proposed that uses stimulated Raman scattering in a single-mode fiber. It is theoretically shown that highly sensitive detection of inertial rotation can be attained by using a synchronously pumped fiber Raman laser operating in the zero-chromatic-dispersion region of the fiber.

Rotation detection by optical heterodyne fiber gyro with frequency output

A fiber gyro with optical heterodyne detection is proposed. The experimental setup has been constructed and tested. Both the frequency difference in the fiber and the path-length difference between counterpropagating waves are eliminated to reduce output drift. An electronic circuit for phase-nulling detection has been constructed, which gives an electronic frequency output in proportion to the rotation rate. Direct frequency modulation of a single-mode laser diode has been adopted to reduce the noise that is due to the backward Rayleigh scattering. A short time resolution of the rotation rate of about 5 deg/h for an integration time of 1 sec. (0.0014 deg/sec) has been achieved with good linearity, for an integration time of 1 sec.