Fabrication And Properties Research On The Novel Near Infrared Broadband Luminescent Glasses And Optical Fibers

With the continuous development of global informationization and increasement of informational amount,the data transmission capacity of optical fiber communication system needs to be further developed and improved,the key is supposed to extend the bandwidth of current fiber amplifier built on Er3+ions,or explore a new ultra-broadband near infrared luminescent material covered the whole silica optical fiber communication window.In particular,the overwhelming arrival of 5G and Internet of Things,puts higher demands on the manufacturing technologies of special doped optical fibers with broadband near infrared luminescence,besides the requirements for fiber amplifiers and lasers.In this thesis,we focused tightly on some existing technical problems and difficulties,making relevant researches on material composition and fabrication methods of special doped optical fibers with near infrared broadband.However,research on the material composition of optical fibers usually consumes huge manpower and material resources,and it is also difficult to control accurately.Therefore,we paid much attention on the near infrared luminescent glass as the center to study the effects of material composition on the spectra of erbium doped and bismuth doped glasses.On the other hand,the fabrication methods of optical fibers were studied,and special doped optical fibers with near infrared emission were prepared.The specific research aspects are as follows.Firstly,the typical near infrared luminescent material,Er3+ doped bismuthate glasses are studied.Bismuthate glasses have abundant glassy structures,so broad near infrared emission can be obtained.However,bismuthate glasses are susceptible to the preparation conditions.On this basis,the effects of glass melting temperature and glass composition on the spectrum of Er3+ are studied.The results show that lower melting temperature favors the emission of Er3+,and higher melting temperature causes clusters of bismuth metal nanoparticles in the glasses,resulting in a decrease in the quality of the glasses.The introduction of CeO2 improves the performance of glasses under high temperature melting by redox reaction.At the same time,energy transfer can effectively suppress the excited state absorption and up-conversion emission of Er3+,and improve the luminescence intensity of near infrared.Secondly,a new method is proposed to fabricate the phosphosilicate glasses with arbitrary SiO2/P2O5,which is not possible preparing by conventional melt quenching method.The new method is termed melt-in-melt.Because of near unlimited possibilities in designing new glass compositions,there is a correspondingly great degree of freedom in the topological engineering of the glass structure,meaning that multiple glass structures can be present simultaneously in the one glass.This in turn greatly affects the luminescent properties of the dopant.As evidence,bismuth ions and erbium ions are chosen as dopants to emphasize the advantages of the process.As a traditional near infrared luminescent material,erbium ions produce a wider luminescence in a variety of glass structures.As a new type of near infrared luminescent material,bismuth ions generate ultra-broadband luminescence due to the transition of d-d orbital,and this broadband emission covers the whole silica fiber communication window,and is expected to become the basic component of the next-generation optical fiber communication system.Thirdly,bismuth and erbium co-doped high birebringence photonic crystal fibers are fabricated and studied.The co-doping of bismuth ions and erbium ions can generate near infrared emissions covering the entire O-,E-,S-,C-and L-fiber communication bands at 830 nm excitation.Specially structured doped fibers should also receive attention compared to the conventional single mode doped fibers,for example,periodic photonic crystal fibers.Because it can change the effective refractive index by designing a series of air hole structures around the core instead of changing it by direct chemical doping.This fiber has many unique properties,including endlessly single mode,enhanced linear and nonlinear properties,and Bessel beam generation to focus light out of the fiber.The structure of structured optical fibres are highly flexible in design.By designing proper air hole structures,high birefringence structured and photonic crystal fibres can easily be achieved.Finally,3D printing technology is introduced to manufacture of optical fibers,and prepares single mode,multi-mode,bismuth and erbium co-doped single mode,bismuth and erbium co-doped multi-core fiber.Traditional chemical vapor deposition or preform stacking technology,followed by ultra-high temperature drawing to produce doped fibers or structured fibers has been commercially successful.However,this traditional fiber manufacturing technology is difficult to achieve complex structures and advanced material compositions at the same time.This limitation will hinder the development of specialty fibers with superiority and new features.The emergence of 3D printing technology has opened up new possibilities for fiber manufacturing.The main process involves UV sensitive monomer preparation,preform printing using 3D printers,fiber core preparation,high-temperature removal of organic binder and fiber drawing.The results show that this method has the potential to break the shackles of the traditional optical fiber manufacturing industry and lay the foundation for the design and manufacture of new optical fibers.