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/mu epsilon and 36 nm/m(-1), respectively. The proposed PCF-MZI shows negligible temperature sensitivity of similar to 4.6 pm/degrees C over the wide temperature range from 25 to 325 degrees 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. (C) 2010 Elsevier B.V. All rights reserved.