万瓦级光纤激光双色镜合成技术

Over 10-kW fiber laser spectral beam combination based on dichromatic mirrors

高功率光纤激光具有光束质量好、转换效率高、热管理方便和柔性传输等优势,在工业加工和国防领域具有广泛的应用需求.目前,受限于光纤中的非线性效应和模式不稳定效应,单链路光纤激光器输出功率的提升遇到了巨大挑战.为突破单链路激光功率限制,本文基于双色镜合成技术,利用两路自研近单模宽谱光纤激光放大器实现了10 kW近单模合束激光输出,合成效率约为98.3%,光束质量因子M^(2)约为1.29.为进一步提升功率,采用三路宽谱激光实现了13.52 kW合束激光输出,合成效率约为96.8%,光束质量因子M~2约为1.61.本文首次在实验上验证了双色镜合成技术的对宽谱激光的功率提升潜力和光束质量保持能力,通过增加合成路数以及提高单路激光功率,有望在保持高光束质量的情况下实现更高功率激光输出.

Owing to the advantages of good beam quality,high conversion efficiency,convenient thermal management and compact structure,high power fiber lasers have been widely desired in industrial processing.So far,the output power has been strictly limited by the nonlinear effects and transverse mode instability.In order to break through the power limitation,here we experimentally demonstrate a power boosting technology called spectral beam combination based on dichromatic mirrors.Firstly,high power fiber amplifiers with different central wavelengths are established for the spectral combination.Secondly,utilizing a dual-beam combined system and two homemade high power fiber amplifiers,an output power of 10 kW is achieved,with a remarkable combination efficiency of 98.3%and a beam quality of M^(2)~1.33.Secondly,using a three-beam combined system,an output power of 13.5 kW is obtained with a combination efficiency of 96.8%and beam quality of M^(2)~1.61.By increasing the number of input beams and their output power as well,we believe that a higher output power can be achieved based on dichromatic mirror spectral beam combination.