Method and apparatus measuring absolute rotation

摘要

Method for measuring absolute rotation with the aid of a light conductive fiber ring interferometer including a light source, a beam dividing arrangement, a light path formed by a light conductive fiber coil, an optical phase modulator which is disposed in the light path and which modulates the light circulating in the light path with a periodic, optical phase modulation at a fundamental frequency f0, and a photodetector for providing an electrical output signal. The light circulating in the light path or an electrical output signal from the photodetector is modulated with at least one mixing frequency f2 in a manner such that an electrical evaluation signal results which has an evaluation frequency f1 which is smaller than that of the fundamental frequency f0 and which is evaluated to determine the absolute rotation of interest.