Development Of Low Zero Dispersion Chalcogenide Fiber And Its Supercontinuum Study

Because of its wide spectral range and strong spatial coherence,supercontinuum sources are potential useful in fileds of defense,medical and scientific research,especially in the mid-infrared band with ultra-wide spectrum,because of its infrared band.Covering most of the molecular fingerprint absorption area,it can be widely used in environmental monitoring,gas molecule detection and other fields.International research on the supercontinuum output of sulfur-based fibers under the pumping of mid-infrared lasers has reached a very high level.The reported step-type fibers include long-wave optics such as As2Se3,As2S3,Ge As Se,Ge Te-Ag I,etc.Parametric amplification(OPA)laser pulse pumping.However,the OPA is bulky and is spatially optically pumped,making it difficult to effectively implement device miniaturization and integration.The micro-structure design or the taper realizes the ZDW wavelength blue shift of the sulfur-based fiber to adapt to the short-wavelength portable commercial laser(such as 2?m mode-locked fiber laser)pumping,thereby realizing the all-fiberized sulfur-based infrared SC spectrum light source.Considering that the actual preparation of the sulfur-based microstructure fiber is too difficult,and it is difficult to shift the ZDW wavelength to less than 2.0 ?m by structural dispersion alone,the mechanical strength of the tapered fiber is low and the SC spectrum output is narrow.In this paper,focusing on material dispersion,the first method of material dispersion control is proposed,which uses the low dispersion halide(Cs I)component to regulate the Ge-Ga-Se matrix sulphur halide(sulfur and halide)glass.Physicochemical properties and infrared optical properties of(Ge Se2)55-(Ga2Se3)25-(Cs I)20 and(Ge Se2)36-(Ga2Se3)24-(Cs I)40 glasses,and Ge-Ga-Se-Cs I glass The preparation process was studied,and the influence of the purification process on the infrared transmission spectrum of the glass was compared.Then the material dispersion of the two glasses was fitted by the Sellmeier equation,and the specific effects of the material composition on the dispersion control were studied.The sulphur-halogen fiber preform was extruded by skin extrusion method.Finally,the fiber drawing experiment was carried out on the two glasses by the protection of the polymer.The fiber-forming properties of the two chalcohalide glasses were verified and supercontinuum test was carried out.Experiments have played an important role in achieving all-fiber infrared SC light sources and promoting the development of infrared optics.The first chapter of this paper is an introduction,which briefly introduces the mid-infrared supercontinuum,reviews the research status of supercontinuum in soft glass in recent years,and focuses on the research progress of infrared supercontinuum of sulfur-based fiber,and puts forward the work of this work.research content.The second chapter introduces the basic theory of chalcohalide glass,studies several chalcohalide glass systems and their structural models,and understands the related properties of chalcohalide glass,found that this glass system may meet the requirements of low dispersion chalcogenide glass.The third chapter mainly introduces the preparation method of chalcohalide fiber,as well as various performance tests and methods,including the preparation of glass and optical fiber preforms,fiber drawing,thermal properties of glass,infrared transmission spectrum,refractive index and fiber loss,and Supercontinuum measurement methods,etc.In the fourth chapter,the thermal properties of Ge-Ga-Se-Cs I chalcohalide glass were studied,and the transmission curve of chalcohalide glass was analyzed for the further preparation of optical fiber by distillation and purification of raw materials and improvement of melting curve.The refractive index of the glass was obtained by testing and simulation calculation,and the refractive index of the sulfur-halogen glass was studied by simulation calculation.Finally,the laser damage threshold of the chalcohalide glass was tested and analyzed.In the fifth chapter,an innovative peeling and isolation method was studied for the characteristics of chalcohalide glass.The chalcohalide optical fiber preform was prepared and the suitable polymer protection was found through multiple drawing experiments.Then the fiber loss was analyzed.Finally,OPA pumping is used to obtain a wide supercontinuum spectrum,and fiber laser pumping is tried,which is very important for realizing all-fiber infrared SC light source and promoting the development of infrared optics.The last part is the conclusion,summarizes the main research results obtained in this thesis,and briefly explains the shortcomings in the research process and the issues that need to be discussed in depth in the future work.