Research on a 4×1 fiber signal combiner with high beam quality at a power level of 12kW.

At present, increasing the output power of a single fiber laser is a problem worthy of attention, and a fiber signal combiner which can carry high power and high beam quality is a solution to this problem. In this paper, a high beam quality 4×1 fiber signal combiner was developed. Firstly, the simulation model of a 4×1 fiber signal combiner was established, and the factors affecting the beam quality and the transmission efficiency of combiner were simulated. Secondly, based on corrosion technology, a high beam quality 4×1 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, four Yb-doped fiber lasers with a central wavelength of 1080 nm were used to test the output power and beam quality of combiner. The test result showed that the total output power of the signal combiner was 12.03 kW, the overall transmission efficiency was more than 96%, and the M2 factor was measured to be 4.03.