Paralleled Sagnac interferometer and Mach–Zehnder interferometer for enhanced measurements sensitivity based on Vernier effect

Abstract

In this paper, Vernier effect (VE) was experimentally excited through paralleling Sagnac interferometer (SI) and Mach-Zehnder interferometer (MZI). SI was fabricated by a 38 cm long panda-shaped polarization maintaining fiber (PMF) in the Sagnac loop, while MZI was made through pulling single mode fiber (SMF) into a tapered type fiber. The strain and temperature sensitivities of the paralleled SI and MZI were 51.97 pm/με and 2.94 nm/℃ respectively, which were increased approximately 3 times than an individual SI whose measurement sensitivities of strain and temperature were 18.24 pm/με and 0.98 nm/℃ correspondingly. The theoretical analysis of the single interference and paralleled interferences were verified by the experimental results. The proposed sensor shows simple in fabrication, high sensitivity, and good hysteresis, is a strong competitor in monitoring the strain and temperature.