Strain and temperature sensing characteristics of asymmetric-twin-core PCF-based hybrid Mach-Zehnder interferometer

We investigate the strain and temperature sensing characteristics of an inline hybrid Mach-Zehnder interferometer (HMZI) formed by splicing a short section of asymmetric twin-core photonic crystal fiber (ATC-PCF) between two single mode fibers. For fixed polarization state of input light, two cores due to their asymmetric construction strongly support the propagation of few dominant core-modes, specifically, a lowest-order, and a set of lowest- and higher-order core-modes, respectively; this leads to a unique phase difference between inter-core and intra-core mode fiber interferometers in our ATC-PCF based HMZI. Experimental results reveal that, among different orders of interferometers involved in the HMZI, the interferometer with higher-value of modal refractive index difference exhibit larger phase-shift sensitivity to the surrounding perturbations.