Fiber-optic Interferometric Quasi-Distributed Sensor Using Polarization-Maintaining Fiber

We describe a new sensitive technique for quasi-distributed measuring of temperature and strain. It is based on nonresonant point-like coupling of polarization modes in a birefringent fiber illuminated with a broad band light source. The Fourier transform of output intensity spectrum allows to interrogate simultaneously a number of in-fiber interferometers. High temperature and strain sensitivity have been achieved by using a compact CCD spectrograph.