Spectroscopy analysis of mixed organic liquid detection with Ge20Se60Te20 glass-tapered fiber

In this study, the high-purity Ge20Se60Te20 glass was prepared by melt-quenching method and drawn into a bare glass fiber with a diameter of 450 μm. The minimum transmission loss of this fiber is approximately 3.4 dB/m at 5.9 μm. Then, the fibers were tapered into different waist diameters of 30, 50, 70, and 90 μm. Those tapered fibers were used as sensor for detection of mixed liquid containing different ratios of methanol (CH3OH) and dichloromethane (CH2Cl2) by fiber evanescent wave spectroscopy in situ. Finally, the sensing characteristics of the tapered fibers to the mixed liquid were simulated based on finite-element method. The simulation results were in good agreement with the experimental results.