A Cascade Fiber Optic Sensors for Simultaneous Measurement of Strain and Temperature

A simple and compact cascade fiber optic sensor for simultaneous measurement of temperature and strain is proposed and demonstrated in this letter. The structure consists of a short section of a PANDA fiber and a cascaded fiber Bragg grating (FBG). A Sagnac interferometer was formed in the PANDA fiber by tip coating the gold film. The sensitivities of the PANDA fiber and FBG for the temperature and strain are different, which makes the sensor to have the ability to measure strain and temperature simultaneously. Experimental results show that the maximum errors for the temperature and strain measurements are 0.22 °C and 21.7
μϵ
, respectively. Based on its simple fabrication process and compact size, the sensor described in this letter could be a competitive candidate in remote sensing for the simultaneous measurement of temperature and strain.