Research on high beam quality 3×1 fiber signal combiner

In the high power synthesis schemes based on fiber signal combiner, it is one of the urgent problems to be solved in the current laser field to maintain good beam quality after beam combining. A kind of high beam quality fiber signal combiner was developed. Firstly, the model of a 3×1 fiber signal combiner was established by using simulation software, and the factors affecting the beam quality and transmission efficiency of combiner were simulated, and the theoretical values of optimum parameters of combiner were obtained. Secondly, based on the etched fiber cladding technology, a high beam quality 3×1 fiber signal combiner with an output fiber of 50/400 μm (NA=0.12) was fabricated by using the taper-fused fiber bundles technology according to simulation results. Finally, three 3 kW fiber lasers were used to test the combiner. Under the condition that the total input power is 8.95 kW, the output power after beam combining is 8.62 kW, the overall transmission efficiency is more than 96%, and the beam quality is M²=4.035.