Detani Taishu, Zhao Hua, Wang Peng, Suzuki Taiga, Li Hongpu
Opt Lett. 2021 Mar 1;46(5):949-952. doi: 10.1364/OL.418248.
An all-fiber orbital angular momentum (OAM) mode generator enabling simultaneous generation of the second- and the third-order OAM modes with conversion efficiencies larger than 95% has been proposed and experimentally demonstrated, which is realized by using a high-order helical long-period fiber grating (HLPG) written in a thinned four-mode fiber. This is the first time, to the best of our knowledge, that two such OAM modes have been simultaneously obtained at wavelengths ranging from 1450 to 1620 nm by using only one fiber component, i.e., the HLPG. The proposed method provides a new way to simultaneously generate different orders of the OAM modes, which would further expand the OAM's applications to the fields of the optical tweezers, microscopy, and fiber communication, etc.
一种全光纤轨道角动量（OAM）模式发生器已被提出并通过实验证明，它能够同时产生转换效率大于95%的二阶和三阶OAM模式，这是通过在变细的四模光纤中写入高阶螺旋长周期光纤光栅（HLPG）来实现的。据我们所知，这是首次仅使用一个光纤组件（即HLPG）在1450至1620 nm波长范围内同时获得两种这样的OAM模式。所提出的方法为同时产生不同阶次的OAM模式提供了一种新途径，这将进一步扩大OAM在光镊、显微镜和光纤通信等领域的应用。
