High-sensitivity transverse-load and high-temperature sensor based on the cascaded Vernier effect

In this paper, we demonstrate a novel, to the best of our knowledge, transverse-load and high-temperature sensor based on the cascaded Vernier effect. Two Fabry–Perot interferometers fabricated by a piece of hollow-core fiber (HCF) and a piece of polarization-maintaining photonic crystal fiber (PM-PCF) are connected by a long part of single-mode fiber with a length of 1 m, and play the roles of transverse-load sensor and high-temperature sensor, respectively. The sensitivity of not only the transverse load but also that of temperature can be enhanced by the Vernier effect. The sensitivity of the transverse load is raised by 7.7 times to 5.84 nm/N, and the temperature sensitivities increased by 5.5 and 5.9 times to − 0.0689 n m / ∘ C and − 0.1038 n m / ∘ C within the temperature range of 50–400°C to 400–900°C. Moreover, both the HCF cavity and PM-PCF cavity can be split and combined flexibly. Hence, such a sensor could have great potential in sensing applications.