In this work, we demonstrated the double-cladding Tm/Al co-doped photonic crystal fiber (PCF) by laser additive manufacturing. The measurements show that the fiber was heavily doped with a Tm3+ concentration of 2.13% (mass fraction) without any crystallization. The splicing property of PCF was studied, and the integrity of the PCF air holes was maintained during the splicing process. The PCF with combiner pigtail has a splice loss of 0.23 dB. The all-fiber Tm/Al co-doped PCF amplifier system achieves a slope efficiency of 13% at 1948 nm with an output laser power of nearly 1.59 W. An upconversion process was also observed under laser excitation with a 1064 nm pulse. This method provides a new idea to deal with Tm-doped PCF fabrication and promotes the promising application of 2 µm fiber lasers.

kW级高功率激光柔性传输是激光清洗、激光焊接、激光刻蚀等高功率激光加工领域中必备的环节，而实现高功率激光低损耗传输的光纤是其关键器件。目前高功率激光传输光纤采用大芯径传能光纤，仍然存在着弯曲损耗大、柔性差等问题，并且使用过程中要经常维护。华南师范大学特种光纤研究中心提出一种大芯径空气包层微结构光纤，利用包层的空气孔可以极大降低激光泄露的风险，降低光纤制备过程中对耐高温涂敷层的严苛要求，实验结果证实该光纤在室温无制冷条件下可实现kW级激光传输，从而为10 kW级高功率激光柔性传输奠定基础。

In this work, we proposed a feasible method to prepare the Bi/Al co-doped silica glass by using laser additive manufacturing technology. Bi was uniformly doped into the silica matrix. The hydroxyl content of the glass sample was measured to be 29.36 ppm. Using an 808 nm laser diode as the excitation source, a broadband near-infrared emission from 1000 to 1600 nm was obtained. The emission peak was centered at 1249 nm, and the corresponding FWHM was more than 400 nm. The results show that the laser additive manufacturing technology is promising to fabricate highly homogeneous Bi-doped core materials with broader emission band, which is beneficial to solving the communication capacity crunch and promotes the development of fiber communication in the upcoming fifth and sixth generation systems.