Laser injecting method from free space beam to single-mode fiber using single lens

The laser injecting efficiency from free space to small-mode-area single mode fiber is a crucial issue during the operation of supercontinuum generation. Compared with the difficult adjustment and fragile fiber end face using single lens method, an improved laser injecting method is presented. A large-mode-area single mode fiber is employed to couple the free space laser and spliced to the small-mode-area single mode fiber. The experimental results show that the optical efficiency of supercontinuum generation is greatly increased using the improved laser injecting system, whose coupling efficiency is more than 60% due to the easy operation.