Research On The Fiber Signal Combiner With High Beam Quality At A Power Level Of 10kW

The incoherent beam synthesis technology based on fiber signal combiner is an effective solution to get high output power of fiber laser.In the pursuit of high output power,high beam quality is also a key parameter to be taken into account by the fiber signal combiner.In this paper,the fiber signal combiner with high beam quality and high output power of ten thousand watts is studied theoretically and experimentally.The main contents of this paper include the following aspects:Firstly,the development history of fiber lasers and the bottleneck problems of high power fiber laser are reviewed.Secondly,the research status of fiber signal combiner at home and abroad is introduced.It is pointed out that the fiber signal combiner which can give consideration to both high power and high beam quality is an urgent problem to be solved.The taper theory of single fiber and two principles are introduced.Three-dimensional models of 3×1 and 4×1 fiber signal combiner are established.The effects of several parameters on the performance of the two fiber signal combiners are analyzed respectively.The optimum parameters of the two fiber signal combiners are obtained.The fabrication steps of fiber signal combiner based on tubing method are introduced in detail.The 3×1 and 4×1 fiber signal combiners are fabricated by fiber corrosion technology.The performance of these fiber signal combiners was tested,and the test results showed that:The output power of the 3×1 fiber signal combiner is8.62k W,the overall transmission efficiency is greater than 96%,and the beam quality M~2 is 4.03;the output power of the 4×1 fiber signal combiner is 12.03k W,and the overall transmission efficiency is greater than 96%.The beam quality M~2 is 4.03.Experimental results show that it is effective to improve the beam quality by increasing the core duty ratio of taper-fused fiber bundle.