Temperature self-compensating fiber-optic misalignment sensor based on Cu-MOFs/PAN film cavity for detecting dimethyl carbonate gas

Dimethyl carbonate (DMC) plays an important role in the electrolyte of new energy, so the importance of DMC gas detection is self-evident. This article reports a fiber-optic DMC gas sensor based on metal organic frameworks (MOFs). The fiber structure consists of two sections of four mode optical fiber (FMF) and one section of splicing misaligned centerless optical fiber (COF). The sensing arm of Mach-zehnder interferometer (MZI) is constructed by filling Cu-MOFs/polyacrylonitrile (PAN) by electrospinning in the misalignment gap between COF and FMF, with the COF serving as the reference arm. At the same time, surface plasmon resonance (SPR) is excited by depositing a Ag/zinc oxide (ZnO) film on the other side of the COF, and PAN is deposited as a temperature sensitive layer by electrospinning. The research results indicate that the DMC sensitivity of MZI is 93.25 pm/ppm, and the temperature sensitivity of SPR is 596.2 pm/°C. The DMC gas concentration and temperature errors based on dual parameter matrix demodulation are E (ΔC) = 1.38 % and E (ΔT) = 1.80 % respectively. Finally, the changes of DMC gas concentration and temperature during the leakage of lithium battery are successfully analyzed. This sensor has the advantages of simple manufacturing, small size, and high sensitivity, and has potential application prospects in terms of lithium battery monitoring.