Simultaneous measurement of trace dimethyl methyl phosphate and temperature using all fiber Michaelson interferometer
Abstract:
All fiber Michaelson interferometer cascaded fiber Bragg grating (FBG) sensor for simultaneous measurement of trace dimethyl methyl phosphate and temperature is proposed. One end of the four-core fiber (FCF) is spliced with a multimode fiber (MMF), the other end is flattened and evaporated with silver film to enhance reflection, and the Michelson interference structure is formed. The grating is engraved in the single-mode fiber (SMF) core and spliced with MMF, then the Michelson interference cascaded FBG, FBG-MMF-FCF sensor is obtained. The sensing film, MnCo2O4 is coated on the surface of FCF, and the structure, elemental composition and morphology of MnCo2O4 were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The sensitivity and the detection limit of DMMP are 86.44 dB/ppm and 0.1767 ppb, respectively. The response/recovery time is about 14/10 s. the temperature sensitivity can be compensated and calculated as 0.069 nm/°C. The sensor has good selectivity and stability, and has a good application prospect in high sensitivity detection of trace DMMP vapor.
