Coherent Polarization Beam Combining of Four High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique

We demonstrate a coherent polarization beam combining (CPBC) of four all polarization-maintained high-power fiber amplifiers with a total output power of 60 W, using the single-frequency dithering technique. When the control system is in the closed loop, the intensity profile is steady and the phase noise can be suppressed effectively. The experimental results show that the combining efficiency of the whole system is as high as 90% in the circumstance of imbalance power ratios of the four beams. The technique used in this letter can be straightforwardly scaled to CPBC of a large array of high-power fiber amplifiers.