Study On Preparation Of Ge-Se-Te Chalcogenide Glass Tapered Fiber And Its Sensing Properties For Organic Solutions

Chalcogenide glasses?ChGs?are based on one or more of chemical elements,including sulfur?S?,selenium?Se?,and tellurium?Te?,in group VIA of the periodic table and the addition of other elements,such as germanium?Ge?,arsenic?As?,and antimony?Sb?.The chalcogenide glass fiber has excellent transmission characteristics in the far-infrared region as well as anti-crystallization,anti-corrosion,high sensitivity,etc.Therefore,sulfur-based chalcogenide glass fibers have unique advantages in liquid and gas detection as well as biochemistry,medicine,and food monitoring.Therefore,it is of long-term practical significance to explore a new type of highly sensitive mid and far-infrared chalcogenide glass fiber sensors.In this paper,a new high-purity Ge₂₀Se₆₀Te₂₀ glass with high purity was prepared by multiple distillation purification and melt-quenching methods,and its thermal and optical properties were tested.Then the Ge₂₀Se₆₀Te₂₀ glass was drawn into bare fibers and the fibers were tapered into different waist diameters by self-made taper platform.Finally,the sensing experiments on different concentrations of mixed solution were tested,which the possibility of using sulfur-based fiber for mixed liquid sensing was confirmed.And we also make the simulation experiment by COMSOL software,which results were in good agreement with the experimental results.The optimal cone parameters of tapered fiber were obtained according to the experimental and simulation results.In chapter 1,the research background of infrared fiber sensors and the development status and trends in recent decades were introduced first.The parameters that need to be paid attention to when the chalcogenide glass fibers were used in the sensing field,such as fiber component,fiber diameter,fiber structure,and coating are expounded in detail.The application fields for chalcogenide glass fibers were also introduced.Finally,the research content and research significance of this paper are put forward.The second chapter is mainly the theoretical part,which briefly describes the theory of fiber inner total reflection and the mechanism of fiber losses.The background and principle of fiber evanescent wave spectroscopy are emphasized,especially the evanescent wave theory of tapered fiber and coated fiber.In chapter 3,the purification and preparation process of high purity Ge₂₀Se₆₀Te₂₀ chalcogenide glass,and the optical and thermal properties of the glass samples were tested.Then,the preparation and loss test of Ge₂₀Se₆₀Te₂₀ chalcogenide glass fiber were introduced.Next,the tapered fiber with different waist diameter of 30,50,70 and 90 ?m was obtained by tapering.Finally,the sensing experiments were carried out on different concentrations of mixed liquid.The fourth chapter mainly analyzes the performance test results of Ge₂₀Se₆₀Te₂₀ chalcogenide glass and optical fiber,and analyzes the absorption spectrum of Ge₂₀Se₆₀Te₂₀ chalcogenide glass fiber.The mixed liquid corresponding to the characteristic absorption peak is described in detail.The influence of different waist diameters on fiber sensing optimizes the diameter of the waist.Finally,the sensitivity of fiber sensing is calculated and analyzed.The fifth chapter establishes the fiber optic sensing simulation model established by Comsol software,and the simulation experiments were carried out on the sensing experiments.By comparing the analysis experiments and the simulation results,the appropriate tapered waist diameters obtained by the simulation are consistent with the experimental results.The sixth chapter summarizes the research results of this thesis and prospect.The shortcomings of the experiment and the direction of improvement are proposed.