Selectively toluene-filled photonic crystal fiber Sagnac interferometer with high sensitivity for temperature sensing applications

Abstract

In this paper, we theoretically and numerically investigate toluene-filled polarization maintaining photonic crystal fibers (PMPCFs) for temperature sensing application via Sagnac interferometer. We designed a PMPCF with a birefringence of 8.68 × 10−5, a relative birefringence sensitivity of 26% for 5 °C variation and sensitivity of −11 nm/°C around 25 °C. We study the effects of hole dimensions and fabrication imperfections on the performance of the proposed PMPCF and demonstrate that the PMPCF has a good toleration to any geometrical induced imperfections in the fabrication process of the fiber. Furthermore, we show that the spectral range of the sensor can be easily improved (to values larger than 137 nm) by decreasing the infiltration length of the PMPCF. Keywords: Photonic crystal fiber, Sagnac interferometer, Polarization maintaining fiber, Optical fiber temperature sensor