Simultaneous measurement of temperature and pressure with serially spliced reflecting birefringent optical fibers

Abstract

The simultaneous measurement of temperature and pressure using the reflected light of two high birefringent fibers is studied. These two fibers are spliced and twisted 45 degrees. The resulting spectrum contains the interference caused by the birefringence of each fiber, and the differential and sum of the frequency. The obtained spectrum is processed with a band-pass filter to get the spectrum of each fiber. The pressure and the temperature are demodulated using the peak-tracking method. As a result, the pressure and the temperature sensitivity of these individual fibers are obtained as 3.2nm/MPa and -1.6nm/K for the PANDA fiber, and 3.2nm/MPa and negligible temperature sensitivity for the PM-PCF. This method produces an easily encapsulated, highly sensitive temperature and pressure sensor without any additional type of sensor.