Abstract: A fiber-optic laser gyroscope having phase sensitive detecting means which can reduce rotation rate measurement errors. In the fiber-optic laser gyroscope, errors due to the relative intensity difference between two consecutive pulses, which was an error factor in rotation rate measurement through time interval measurement between two adjacent pulses, can be eliminated by having a phase sensitive detection means which may extract and detect only components having the same phase as that of a phase-modulated signal from components having the same frequency as that of a phase-modulated signal. An output from the phase sensitive detecting means has an additional characteristic of being linearly proportional to rotation rate. The fiber-optic laser gyroscope of the present invention, therefore, has a characteristic of a relatively simple signal processing compared to conventional interferometric fiber gyroscopes.

Abstract: An optical fiber polarization scrambler decreasing the degree of polarization (DOP) of light efficiently using at least two optical fiber birefringence modulators (10, 11) and an operating parameter input method for the same. Birefringence modulators are constructed with hollow cylindrical piezo devices (10, 11) and a strand of optical fiber (30) wound continuously on the outer walls of the piezo devices (10, 11). An angle between the birefringence modulators consisting of the optical fiber polarization scrambler is configured to compensate the effect of circular birefringence. A method for exactly configuring birefringence modulation frequency and birefringence modulation amplitude to achieve effective polarization scrambling for the optical fiber polarization scrambler is also provided.

Abstract: An optical fiber polarization controller which has compact size by employing wave plates made of short sections of a first optical fiber having inherent birefringence such as a polarization maintaining optical fiber. In the control of the polarization state of input light, a second optical fiber, for example a single mode fiber, connected to the first optical fiber is twisted using fixing knobs, thereby rotating the birefringence axis of the first optical fiber with respect to the second optical fiber.