Simultaneous distributed measurement of strain and temperature by polarization maintaining fiber Bragg grating based on optical frequency domain reflectometry

In this paper, a simultaneous strain and temperature measurement method using a polarization maintaining and absorption reducing (PANDA) fiber is applied to a distributed sensing system based on optical frequency domain reflectometry (OFDR). A fiber Bragg grating (FBG) whose length is 100 mm is inscribed into a PANDA fiber to form a long-length PANDA-FBG. We demonstrated simultaneous measurements of strain and temperature distributions experimentally. In experiments the long-length PANDA-FBG was bonded on a steel plate and various strains and temperatures were applied at the same time to the plate. Consequently strain and temperature were successfully discriminated. However, larger errors were observed for distributed measurement results.