A unique orbital angular momentum (OAM) optical amplifier based on a ring-core fiber doped with lead sulfide (PbS) is realized for the first time in this study. The PbS-doped ring-core fiber is fabricated using the modified chemical vapor deposition method. The cross-sectional microscope image of the fiber is obtained. The difference in the refractive index between the ring core and the fiber cladding measured by a three-dimensional refractive index tester reaches 1%. The sulfur and lead content in the ring-core of the PbS-doped ring-core fiber is confirmed by energy spectrum analysis. A first-order OAM optical amplifier is built based on the PbS-doped ring-core fiber. The experiment confirms that the air-hole PbS-doped ring-core fiber can support the OAM |l| = 1 modes. In addition, 2.3 dB of on–off gain is obtained for the OAM |l| = 1 modes at 1,550 nm. The fluorescence spectrum obtained using the backward pumping method ranges from 1,100 to 1,600 nm.

本研究首次实现了基于掺杂有硫化铅（PbS）的环形芯光纤的独特的轨道角动量（OAM）光放大器。掺杂PbS的环形纤芯纤维是使用改进的化学气相沉积方法制造的。获得纤维的横截面显微镜图像。用三维折射率测试仪测得的环形芯和纤维包层之间的折射率差达到1％。掺杂了PbS的环形纤芯纤维的环形纤芯中的硫和铅含量通过能谱分析得到了证实。基于掺杂PbS的环形芯光纤构建了一阶OAM光放大器。实验证实，掺有空气孔的PbS环形纤芯光纤可以支持OAM。升| = 1个模式。此外，对于OAM | |获得2.3 dB的开关增益。升| = 1,550 nm下的1个模式。使用反向泵浦法获得的荧光光谱范围为1,100至1,600 nm。