γ射线等高能射线会使掺镱光纤产生暗化效应,降低掺镱光纤激光器长时间运行的可靠性。测量了γ射线辐照总剂量对大模场掺镱光纤的损耗特性,结果表明,待测光纤损耗随辐照总剂量线性增大。基于辐照导致的损耗的测量结果和速率方程模型,研究了辐照损耗产生后具有不同结构参数的激光器的效率变化。结果显示,仅考虑辐照损耗效应时,976 nm泵浦的光纤放大器对辐照附加损耗的敏感性最低;待测光纤最优信号光的中心波长为1070 nm,但是在1060~1100 nm范围内最小与最大效率仅相差2%。本研究从掺镱光纤激光器系统层面开展探索研究,为后续激光器的设计和实际应用提供了参考。

High energy radiation such as γ ray induces a darkening effect on Yb-doped fiber (YDF), adversely affecting the reliability of Yb-doped fiber laser (YDFL). In this study, we assess the influence of the total dose of γ ray on the loss of large mode area YDF. The results show that the radiation induced loss (RIL) of the tested fiber linearly increases with the total dose. The optical efficiency of YDFL with different structural parameters after the generation of RIL is then investigated based on the measured value of RIL and rate equation model. The amplifier scheme pumped with 976-nm laser diodes exhibits the least sensitivity to the total dose of γ ray. The optimized central wavelength used herein is 1070 nm for the YDF; however, the efficiency difference is only 2% for wavelengths from 1060 nm to 1100 nm. This paper performs the research based on the YDFL system, providing a reference for further YDFL design and applications.