Simultaneously measuring temperature and strain using optical fiber microcavities

Abstract

Presents an optical fiber sensor capable of simultaneously measuring both axial strain and temperature. The sensor configuration is composed of a 70 /spl mu/m in-line fiber etalon (ILFE) cascaded with a 170 /spl mu/m intrinsic Fabry-Perot (IFP) sensor to form a lead in-sensitive, localized, 240 /spl mu/m gauge-length dual parameter sensor. The sensor response from this configuration is interrogated using coherence division multiplexing based on white light interferometry, and using pseudoheterodyning demodulation. The results obtained in a simultaneously varying temperature and strain field by the fiber sensor are compared with a semiconductor temperature gauge and a resistance strain gauge. The correlation is very good.