METHOD AND DEVICE FOR THE MEASUREMENT OF THE PHASE SHIFT OF THE WAVES IN A RING INTERFEROMETER

摘要

1. A method of measuring the phase difference of electromagnetic waves circulating in opposite sense in a ring interferometer, comprising the step of generating an electromagnetic wave, separating this electromagnetic wave into two phase components which are fed into the end of the ring in order to generate the waves ciculating in opposite sense, modulating the phases of the two waves in periodical and reciprocal manner, recombining the two waves at the ends of the ring and detecting the recombined waves, characterized in that in the modulating step the phase of the two waves circulating in opposite sense are modulated at least at one end of the ring according to a function satisfying the relation PHI(t)=PHI(t+2 tau), wherein tau is the time necessary for each wave for passing through the optical way provided by the ring, and at that the step of detecting the phase difference between the two recombined waves is carried outs by measuring, at the frequency (1/2 tau) or at an entire multiple (k) of this frequency the optical power of the component of the recombined waves proportional to the sine of the phase difference between the waves.