国产光纤实现直接抽运全光纤化3000 W级激光输出

基于国产光纤构建了直接抽运全光纤化主控振荡器功率放大器结构光纤激光器, 放大级分别采用武汉烽火锐光科技有限公司和中国电子科技集团公司第四十六研究所提供的国产20/400 μm掺镱双包层光纤作为增益光纤, 通过全国产化放大级实现了3050和3092 W的1080 nm激光输出. 放大级提取效率分别为67.3%和68.2%, 光-光效率分别为63.0%和63.9%. 据可查询资料, 这是公开报道的直接抽运全光纤激光输出的最高水平, 同时由于采用了国产光纤作为放大级增益光纤, 表明国产光纤具备了3 kW级光纤激光器输出能力. 通过国产光纤横截端面以及光纤熔接显微镜图像实验分析知, 光纤制造工艺的不足是导致国产光纤激光器效率低的主要原因. 继续改进光纤工艺, 提升抽运功率, 优化光纤长度, 有望实现更高功率的全国产化光纤激光器输出.

3000 W direct-pumping all-fiber laser based on domestically produced fiber

In this paper we present an all-fiber directly pumped fiber laser in master oscillator power amplifier configuration based on domestically manufactured fibers. In the amplifier stage of the laser, the gain fibers adopt the 20/400 μm Yb-doped double cladding fibers manufactured separately by Wuhan Fiber Home Technologies Group and China Electronics Technology Group Corporation No. 46 Research Institute in two individual experiments. Via this homemade amplifier stage, the system achieves a 1080 nm fiber laser with output powers of 3050 W and 3092 W respectively with two types of fibers. When the gain fiber of the amplifier adopts the YDF manufactured by Wuhan Fiber Home Technologies Group, the corresponding extraction efficiency and the optical-to-optical efficiency reach 67.3% and 63.0% respectively. No residual pump laser is found in the spectrum of output laser, and the beam quality is measured to be M²<2. Similarly, when the gain fiber of the amplifier adopts the YDF manufactured by China Electronics Technology Group Corporation No. 46 Research Institute, the corresponding extraction efficiency and the optical-to-optical efficiency reach 68.2% and 63.9% respectively. To the best of our knowledge, this is the best result ever reported for directly pumped all-fiber laser. Meanwhile, as we use the domestically manufactured fiber as the gain fiber in the amplifier stage, the result verifies the usage of homemade active fibers in 3-kilowatt level fiber laser. By combining the results of the high power fiber laser, the low efficiency of domestic fiber laser in our experiment might be explained to be due to defects in fiber manufacturing process, the inhomogeneous refractive index of the core, structural flaw of the homemade fiber observed by the microscopic images of the cross section and the splicing fuse of homemade fibers. The main difficulty of these two experiments lies in the heat dissipation of the gain fiber in the amplifier stage. Also, due to the restriction of experimental condition, photodarkening test is unable to run for a longer period of time, which is the focus of our further work. Therefore, measures such as refining fiber manufacturing techniques, increasing pump power and optimizing the length of fiber are suggested to be taken in order to obtain a higher output power from homemade fiber laser.