Spatial-Division Multiplexed Mach–Zehnder Interferometers in Heterogeneous Multicore Fiber for Multiparameter Measurement

We propose and demonstrate a novel spatial-division multiplexed Mach-Zehnder interferometer (MZI) structure in heterogeneous multicore fiber (MCF) for simultaneous measurement of temperature and strain. The MZI structure is constituted of dual-tapered regions along heterogeneous MCF by using electrical arc discharge. Different spatial channels (cores) in heterogeneous MCF have dissimilar responses to the outer environment. With our in-house developed low-loss fan-in/fan-out devices, we experimentally achieved the temperature sensitivity of 47.37 pm/°C for the central core and 53.20 pm/°C for the outer core and strain sensitivity of 1.10 pm/με for the central core and 0.84 pm/με for the outer core. Using the temperature-strain joint matrix, the cross sensitivity is eliminated, and the relative measurement error is less than 5%. The spatial-division multiplexed interferometric sensors embedded in the telecommunication-grade MCF show great potential for multiparameter sensing.