Fiber-optic gyroscope.

摘要

Fiber-optic gyroscopes are normally provided with an independent photodetector for detecting the interfering beams. The existence of the independent photodetector requires two beam dividing-and-combining devices for equalizing the experiences of the clockwise-spreading beam and the counterclockwise-spreading beam. Instead of the independent photodetector, the light source itself or a monitoring photodiode may be used to detect the interfering beams by the change of driving current, applied voltage or photocurrent. Optimum light sources, interposition of polarizer, position of depolarizer and use of birefringent material as polarizer are explained.