Passive coherent combination of all-fiber multichannel laser based on optical feed-back loop cavity

An all-fiber multichannel laser configuration of coherent beam combining with an optical feed-back ring cavity is reported. The passive coherent combining of multichannel Yb-doped fiber amplifiers is achieved with the ring cavity. The traditional problem of energy dissipation to side lode for lower aperture filling is solved via the all-fiber laser configuration, and good beam quality is maintained. The coherent beam combination of four Yb-doped fiber amplifiers is experimentally demonstrated. Stable combination shapes with temporal and spatial characteristic are achieved. The efficiency of coherent combination is up to 96.1%, and it is an excellent result for fiber laser coherent beam combining.