Multi-Components Interferometer Based on Partially Filled Dual-Core Photonic Crystal Fiber for Temperature and Strain Sensing

A multi-components interferometer based on partially filled dual-core photonic crystal fiber (D-C PCF) was fabricated for measuring temperature and strain. The partially filled D-C PCF was prepared by manual gluing method, and the cladding air holes surrounding one core were selectively filled with refractive index liquid while remaining other air holes unfilled. A multi-components interference with a large spectrum envelope and fine interference fringes was observed in the transmission spectrum. Theoretical and experimental investigations revealed that the large spectrum envelope was originated from the interference between the fundamental modes of two cores of the PCF, while the fine interference fringes were generated by the interference between the fundamental mode and higher order modes in one core that surrounded by unfilled air holes. The proposed device can be used to monitor temperature and strain simultaneously through matrix demodulation, with a high temperature sensitivity of 5.43 nm/°C.