Highly sensitive temperature and strain sensor based on an antiresonanthollow core fiber probe with the Vernier effect

A highly sensitive temperature and strain sensor based on an antiresonant hollow core fiber (ARHCF) probe with the Vernier effect is proposed and experimentally demonstrated. The ARHCF probe is used as a reference interferometer by sandwiching an ARHCF, which is insensitive to temperature, strain, and refractive index, between a single-mode fiber (SMF) and a polarization-maintaining fiber (PMF). The polarization mode interferometer (PMI), fabricated by splicing a section of PMF with a fiber polarizer at a 45-degree angle, works as a sensing interferometer. The Vernier effect is introduced by connecting the reference interferometer and the PMI in parallel. The experimental results show that by introducing the Vernier effect, the temperature sensitivity is improved from -1.68 to -15.7nm/^∘C and the strain sensitivity is improved from 5.09 to 47.65 pm/µε. The magnification is consistent with the theoretical results. The reference segment of the proposed sensor is not affected by ambient factors, which provides a new strategy and idea for the development of multiparameter sensors based on the Vernier effect.