Optical heterodyne processing method of mechanically induced phasefluctuations of guided modes in a birefringent single-mode fiber

A method is described for carrying out statistical processing of the individual phases of all the modes guided in a perturbed birefringent single-mode fiber. The method is based on optical heterodyne detection processes using a signal beam with orthogonal linearly polarized two-frequency components and a local oscillator beam. All the time-varying phases of the guided modes are taken out separately and processed to offer their power spectra and correlation functions from which the phase fluctuations can be evaluated statistically