Study On The Laser Characteristic Of Tm³⁺-doped Double-cladding Fiber

The thulium-doped fiber laser whose output wavelength is 2 micron plays an important role in modern military technology(electrooptical countermeasures),biomed icine and lidar.As the core equipment,the preparation technology of thulium-doped double-cladding fiber has been mastered by foreign research team,which has limited the development of the thulium-fiber-using equipment home.This paper aims to research the laser characteristic of thulium-doped fiber prepared by our team,in order to prepare high slope efficiency and high output power fiber,breaking the monopoly of foreign countries.Firstly,we modify the velocity equation and solve it using the runge-kutta solution.,then simulate and analyse the influence of thulium-ion-doped concentration and fiber length to the laser characteristic.Using the Modified Chemical Vapor Deposition and solution or vapour doping technology,we prepared six kinds thulium-doped perform,then draw them to double-cladding fiber.We establish the thulium-doped fiber laser system and test the laser characteristic(slope efficiency,laser wavelength,threshold) of six thulium-doped double-cladding fiber and the influence of bend diameter and different pump wavelength to the laser characteristic,conclusion as follows:1.The minimum slope efficiency is 27.93%,the maximum is 43.23%,threshold changes from 9.2W to 14.25W,output wavelength is between 2013nm and 2043nm;2.Using DCTDF-M004 as gain medium,small bend diameter doesn't always lead to high slope efficiency;bend diameter has ignore influence on threshold and output wavelength;3.The appropriate pump wavelength for DCTDF-M006 is around 791nm,corresponding to the maximum slope efficiency 43.39%;the output wavelength shifts red with the pump wavelength increases;the change of pump wavelength has ignore influence to the threshold.Analyse the test result and establish foundation for preparing high performance fiber.