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Preparation And Research Of Yb-doped Large-mode-area Active Silica Fiber

Posted on:2015-10-20Degree:MasterType:Thesis
Country:ChinaCandidate:T F ShiFull Text:PDF
GTID:2298330452454324Subject:Optics
Abstract/Summary:PDF Full Text Request
This paper mainly studied Yb-doped large-mode-area active silica fiber fromfour aspects of design, fabrication, testing, and application. Six different kinds ofYb-doped large-mode-area active optical fiber were prepared by CDS+MCVDmethod, and the geometric parameters, absorption properties, laser performance etc.were tested. Finally,700W and303W high power fiber laser were obtained by usingall fiber structure lasers and laser amplifiers. The main research contents are asfollows:1. Several new large-mode optical fiber preparations and doping methods oflarge-mode-area active fiber were reviewed and summarized from domestic andforeign developments, and the difficult development problems of large-mode-areaactive fiber has also been concluded.2. With20μm and30μm single structure of large mode field diameter,19-coredouble-clad fibers were designed based on the coupled-mode theory. By thesimulation and analysis of Rsoft software,6000μm2and13063μm2large mode areawith excellent beam quality were obtained based on the core spacing was22μm and30μm respectively, and the changes of super-modes were also studied along thetransmission distance.3. System structure, characteristics and advantages of CDS+MCVD were analyzedand reviewed, optimized and calibrated the CDS+MCVD so that it can be prepared ina7mm core diameter,10000ppm or more doping concentration, and even withoutthe effect of large clusters large mode area field fiber preforms.4. Analyzed and discussed the mechanism and method for inhibiting the Yb3+photodarkening effects, and set SiO2, P2O5, Al2O3, Ce2O3, Yb2O3as the corecomponent, prepared octagonal fiber preform with the number of T1~T6. Octagonaldouble-clad large-mode-area active fibers were manufactured by the CDS+MCVDsystem.5. The principle of thin beam scanning method to test optical fiber preform wasanalyzed and the refractive index profile of T1~T6fiber preforms were test by using the PK2600analyzer. Test the geometric parameters, absorption spectroscopy andlaser performance parameters of T1~T6fibers and the results show that T2fiber isthe most excellent one.6. Cutting and welding techniques of the large core fiber were studied, and getting agood cut face and excellent welding quality; Designed all-fiber structure fiber lasersand fiber amplifiers, separately obtained700W laser output with slope efficiency of54.2%and303W laser output with the slope efficiency of56.3%. Laser output andamplification characteristics were analyzed in the follows.7. Several laser combining technologies were simply summarized, pointed out that anall-fiber passive coherent combining technology has become an importantdevelopment direction of the laser combining technology. Designed two all-fiberpassive coherent combining technical solutions, and analyzed and reviewed theapplication of large-mode-area optical fiber in these solutions.
Keywords/Search Tags:large-mode-area fiber, all-vapor doing technique, all-fiber laser, lasercombing technology
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