A spatial-division multiplexed multi-parameter Brillouin sensor based on an etched weakly-coupled few-mode heterogeneous multi-core fiber

Purpose This paper aims to propose and numerically analyze an etched weakly-coupled few-mode heterogeneous multi-core fiber sensor based on spatial-division multiplexed (SDM) Brillouin for simultaneous multiple-parameter measurement. Design/methodology/approach First, an etched weakly-coupled few-mode heterogeneous multi-core fiber (WC-FMH-MCF) is designed to improve the performance of simultaneous multiple-parameter sensing by optimizing the structural parameters of the fiber. The heterogeneous core arrangement and trench-assisted structure can significantly suppress inter-core crosstalk (XT). Then, the designed fiber’s intramodal Brillouin characteristics, such as Brillouin frequency shift (BFS) and Brillouin gain spectrum (BGS), are studied. Finally, the temperature, strain and sample refractive index (SRI) sensing performance in the designed fiber are analyzed and investigated, based on intramodal SBS. Findings The numerical results show that the minimum errors of simultaneous measurement of temperature, strain and SRI are 0.12°C, 2.96 µe and 9.2 × 10–2 RIU, respectively. Originality/value The proposed etched WC-FMH-MCF sensor provides a potential possibility to better improve the performance of multi-parameter simultaneous sensing.