Preparation Of Phosphate Soft Glass And Birefringence Of Polarization Maintaining Fiber

As a kind of special optical fiber,polarization maintaining fiber can maintain the po-larization state of light wave in the process of transmission.In the past 40 years,it has been developing vigorously in many fields,such as optical fiber communication,optical components,sensors,aviation and navigation and military applications.Therefore,polarization maintaining fiber(PMF)has become a key research topic at home and abroad,which has been paid more and more attention by experts and scholars.Researchers use different prin-ciples to make the polarization maintaining fiber obtain higher birefringence.After 1980s,the application of polarization maintaining fiber is becoming more and more diversified.In this paper,the principle of birefringence in polarization maintaining fiber is intro-duced.In addition,a design idea was proposed and a kind of P₂O₅--K₂O--BaO--Al₂O₃ Phos-phate glass material was prepared by ourselves,which has the characteristics of high thermal expansion coefficient and poor thermal expansion coefficient,is used to replace the material with high boron content in the stress zone.At the same time,there is a large difference in thermal expansion between the stress zone and the core or cladding glass,which realizes the material optimization of polarization maintaining fiber.At the same time,the related opti-mization of the water removal process of phosphate glass was carried out in the preparation process.It was found that hydroxyl group(OH--)had a great influence on the optical prop-erties of phosphate glass.By studying the chemical equation of reversible reaction,bubble method and atmosphere protection method were used to optimize the water removal process.Finally,high-quality phosphate glass was prepared.Then,the finite element method is used to analyze the polarization maintaining fibers with different cross-section configurations.Different from the traditional polarization main-taining fibers using quartz and mixture of germanium and boron doping as the stress zone material,phosphate glass is selected as the matrix material of polarization maintaining fibers,and the preparation work is successful.Then,the birefringence of polarization maintaining fibers is simulated by selecting the relevant parameters of the phosphate glass.It is found that the birefringence of polarization maintaining fibers is obviously improved compared with the traditional polarization maintaining fibers.Finally,the geometric birefringence of polarization maintaining fiber based on phosphate glass is studied.The influence of core radian on birefringence is discussed by designing the shape of fiber core.Through simulation experiments,it is found that the birefringence of shuttle shaped core is larger than that of circular or elliptical core,which provides a new idea for further improving the birefringence of polarization maintaining fiber.