Sensitivity-enhanced temperature and strain sensor based on a UFPMF Sagnac loop cascaded with a SCMOF probe

A sensitivity-enhanced temperature and strain sensor based on a fiber Sagnac interferometer (FSI) cascaded with a suspended-core microstructured optical fiber (SCMOF) Fabry-Perot probe is proposed and experimentally demonstrated. The FSI consisted of a certain length of high birefringence ultra-fine polarization maintaining fiber (UFPMF) as the sensing interferometer. The cascaded Fabry-Perot interferometer (FPI) is fabricated by fusion splicing a SCMOF tip with a single mode fiber (SMF) as the reference interferometer. By adjusting the length of the UFPMF in the FSI, the free spectral ranges (FSRs) of the FSI and FPI can be easily made similar, thus creating a Vernier effect and achieving enhanced sensitivity. The experimental results show that under the influence of the Vernier effect, the temperature sensitivity and strain sensitivity of the cascaded sensors are 30.909 nm/celcius and -52.57 pm/& mu;& epsilon;, respectively. With the advantages of simple production, easy fabrication, and high sensitivity, this sensor has a wide application prospect in the fields of aerospace and precision measurement.