Nonincremental interferometric fiber-optic measurement method for simultaneous detection of temperature and strain

A nonincremental interferometric fiber-optic measurement method for simultaneous detection of temperature and strain is reported. The method is based on the joint evaluation of the fiber-optical path length and of the fiber dispersion by means of nonincremental interferometric phase readings at two different wavelengths. The joint use of a low-coherence source and of multiple optical filtering of the interference term permits effective setting up of the method. The experimental results prove a strain measurement precision of approximately 10 micro m in the presence of temperature variation of 30 degrees C.