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Investigation On End-pumped Fiber Combiner

Posted on:2018-02-09Degree:MasterType:Thesis
Country:ChinaCandidate:Y CaoFull Text:PDF
GTID:2348330542481400Subject:Optical engineering
Abstract/Summary:PDF Full Text Request
As the key device of the high power fiber laser,the end combiner plays an important role in deciding the performance of the laser.The function of the pump combiner is coupling several beams of pump laser output from laser diodes into the gain fiber in order to pump the fiber laser.To improve the efficiency of fiber laser,raise the endurable power,and avoid overlarge heat load induced by the insertion loss,it is an important research topic to increase the transmission efficiency of the combiner.In addition,the laser combiner can transfer several beams of fiber laser into one fiber.It is significant to optimize this fiber device in order to achieve output with high power and high beam quality.In this thesis,we carry out research in both kinds of combiners;the main work is demonstrated as follow,Firstly,we theoretically analyze the influence of the structure of the tapered fused bundle(TFB)of the 7×1 end-pumped combiner on its transmission efficiency.The simulation studies the transmission efficiencies of several polarization modes propagating in the pump fibers through the TFB with different taper length to determine the minimum taper length of the TFB.In addition,we compare the transmission efficiencies of different modes' light propagating through the TFB employing the capillaries with different refractive index,from which the requirement of fabricating high transmission efficiency combiner is achieved.At last,we put forward the propose structure of the combiner based on the results of theoretical research.Secondly,we theoretically analyze the mode of splicing between the TFB and output fiber of laser combiners in order to improve the beam quality of the output laser.We explore the influence of the differences in the off-center splicing on the beam quality to achieve an improved splicing plan.Thirdly,we explore the fabricating process of the 7×1 end pump combiner experimentally.The process which includes arraying the pump fibers,tapering the fiber bundle,cleaving the TFB at the taper waist,polishing the end of the TFB and splicing the TFB to the output fiber with the employment of fiber tapering and splicing devices is explored.Furthermore,the transmission efficiency,return loss and the internal operating temperature of one our homemade combiner with high performance are inspected.
Keywords/Search Tags:Fiber laser, Pump combiner, Laser combiner, Transmission efficiency, Beam quality, Fabrication of combiner
PDF Full Text Request
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