Fiber-optic Michelson interferometric trace dimethyl methyl phosphate sensor based on MnO2/ZnO composites film

A dimethyl-methyl phosphonate (DMMP) sensor based on MnO2/ZnO composite film integrated fiber-optic Michelson interference structure is proposed. The sensing structure is formed by a thick taper between a single-mode fiber (SMF) and a four-core fiber (FCF), and then the no-core fiber (NCF) is spliced at the other end of the FCF. To enhance reflection, the silver film was deposited on the end of the NCF, and the fiber optic Michelson interference structure is formed. MnO2/ZnO composite sensing film was deposited on the FCF surface, and the structure, morphology, and properties of the sensing material were analyzed by x-ray diffraction, Scanning electron microscopy, Fourier-transform infrared spectroscopy, x-ray photoelectron spectroscopy, etc. The sensitivity and the response time of the sensor are 0.3478 dB/ppm and 180 s, respectively. The sensor has good selectivity and stability, and it has a good application prospect in trace DMMP detection with high sensitivity.