Spatial-division multiplexing backward Brillouin scattering in dual-core optical fibers for temperature and curvature sensing

We propose a theoretical framework for dual-parameter sensing of temperature and wide-range curvature by exploiting two backward Brillouin scattering peaks in a dual-core fiber (2CF) via spatial-division multiplexing (SDM). By engineering convex and concave refractive index profiles in the inner and outer cores, respectively, we select the optimal group of Brillouin peaks through acoustic modal division multiplexing (AMDM) and SDM, to simulate temperature and curvature sensing. We demonstrate that the sensor featuring temperature sensitivities of 1.092 and 1.126 MHz/^∘C and curvature sensitivities of 5.098×10^-3 and 2.255 MHz/m^-1 exhibits low demodulation errors, with the maximum errors of 0.0921^∘C for temperature and 0.0009 cm^-1 for curvature, respectively. This theoretical scheme offers a feasible strategy for the development of temperature and curvature dual-parameter Brillouin sensors, which may facilitate advanced applications in structural health monitoring.