Highly sensitive strain and bending sensor based on in-line fiber Mach–Zehnder interferometer in solid core large mode area photonic crystal fiber

We have proposed highly sensitive strain and bending sensor with very low temperature sensitivity based on in-line Mach–Zehnder interferometer (MZI) in solid core large mode area photonic crystal fiber (PCF) and experimentally investigated its novel characteristics. The measured strain and bending sensitivities were −3 pm/με and 36 nm/m−1, respectively. The proposed PCF–MZI shows negligible temperature sensitivity of ∼4.6 pm/°C over the wide temperature range from 25 to 325 °C, eliminating the effect of temperature in optical sensing applications. Furthermore, as the fabrication process of the proposed device does not require photo-inscription or complicate fabrication methods, the proposed device is cost effective and has a great potential to be applied in optical sensing systems.