将自由空间光耦合进单模光纤产生超连续谱的实验中,空间光与单模光纤的耦合效率是其中的一个关键问题。常采用的单透镜或显微物镜进行耦合存在耦合效率低、调整难度大、端面易损伤等问题。提出了先将自由空间的光耦合进纤芯尺寸较大的单模光纤,然后将纤芯较大的单模光纤和纤芯较小的单模光纤进行熔接。实验结果表明,改进的耦合系统耦合效率大大提高,达到60％以上,且调整难度降低,光纤端面的损伤概率降低,大大提高了超连续谱产生的效率。

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.