Highly sensitive strain sensor based on a novel Mach–Zehnder mode interferometer with TCF-PCF-TCF structure

We have demonstrated a high-sensitivity strain sensor based on a novel photonic crystal fiber (PCF) interferometer by means of splicing two sections of thin core fibers (TCF) with a piece of PCF between two single mode fibers (SMFs). The proposed MZI has exhibited an excellent fringe visibility as high as 21 dB in air. Particularly, the measurement range was up to 4 me and a strain sensitivity of −1.89 pm/µe was achieved. It was found that the strain sensitivity of the MZI was weekly dependent on the PCF length. The measured sensitivities of the MZI with 25 mm, 30 mm and 35 mm PCF at ∼1590 nm were −1.83 pm/µe, −1.85 pm/µe and −1.77 pm/µe, respectively. Moreover, the temperature characteristics of the sensor were also investigated. Additionally, the sensor has advantages of simplicity of fabrication, low cost, compact size as well as large strain measurement range.