Abstract: Based on Faraday effects in birefringence optical fiber, we study the influence of the polarized style and the style of analysis on the measurement sensitivity of beat-length. This is done by using magneto-optic modulation techniques in which the magnetic gap and magnetic intensity are known. In a commonly used style, the input light is linearly polarized and parallel to the birefringence axis of the fiber, and the two analyzing axes of Wollaston prism make 45° with the birefringence axis of the fiber. In addition to this style, two other experimental styles are found to provide high sensitivity. In one of these styles, the input light is linearly polarized having an angle of 45° with respect to the birefringence axis of the fiber, and the Wollaston prism is parallel to the birefringence axis. In the other style, the input light is circularly polarized and the Wollaston prism is parallel to the birefringence axis. The latter does not require accurate birefringence axis direction at the input end. This makes experiments more convenient and can reduce measurement error due to angle adjustment.

Key words: analyzing style, magneto-optic modulation, polarizing style, sensitivity, beat length