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Theoretical Study Of Some Problems Of Coupled Fiber Laser Array

Posted on:2012-06-20Degree:MasterType:Thesis
Country:ChinaCandidate:L ZhouFull Text:PDF
GTID:2248330392455012Subject:Optics
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Fiber laser has the advantages of compact structure, low threshold value, highconversion efficiency, good beam quality and excellent heat elimination; it has abroad prospect in industrial processing, medical treatment, scientific research andnational defense. But output power of single fiber laser is limited by nonlinear effects,thermal damage, optical damage, and so on. By using coupled fiber laser array,coherent beam combination can be got, and output power can be stacked with a highbeam quality. Coherent beam combination is an effective way to get lasers with highoutput power, high beam quality, high conversion efficiency.Through numerical simulation and theoretical analysis of coherent beamcombination of fiber lasers, this article includes the following segments:(1) Propagation properties and field distributions in the fuse tapered fiber areinvestigated by finite-difference time domain method (FDTD), based on a taperingfunction which is close to the real shape of fuse-tapered fiber. Field distribution andtransmission efficiency of the fuse-tapered fiber in the fundamental-mode Gaussianapproximation are compared with the simulation results finally.(2) A technique to achieve mutually injection phase-locking of fiber lasers by using a45°beam splitter, which can bear high power, is reported and analyzed. Elementarytheoretical investigation on fiber laser array was carried out. Effects of frequencydifferences and structural parameters are investigated. Methods to optimize is alsostudied.(3) Phases in a general coupled-laser-array are theoretically investigated. Phase inquiescent, chaotic and hyperchaotic states are studied. Phase attractors of thecoupled-laser-array are firstly found to exist. Effect of initial phases and couplingstrength are investigated. Based on these result, we presented method to get phase-locking with large permission of frequency differences(4) Stability of phase-locking state in a coupled-laser-array is theoreticallyinvestigated. We have presented a method to investigate the stability of phase-lockingstate. Two tapes of coupled-laser-array with different topological structure are studiedrespectively for examples. Effectiveness of this method is proved by numericalcalculation results.
Keywords/Search Tags:fiber laser, fuse tapered fiber, coherent beam combination, phase-locking, phase attractor, stability
PDF Full Text Request
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