Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA.
Opt Lett. 2012 Sep 1;37(17):3645-7. doi: 10.1364/OL.37.003645.
We propose an approach to efficiently generate and multiplex optical orbital angular momentum (OAM) modes in a fiber with a ring refractive index profile by using multiple coherent inputs from a Gaussian mode. By controlling the phase relationship of the multiple inputs, one can selectively generate OAM modes of different states l. By controlling both the amplitude and phase of the multiple inputs, multiple OAM modes can be generated simultaneously without additional loss coming from multiplexing. We show, by simulation, the generation of OAM modes (OAM state |l|<3) with mode purity greater than 99%. The power loss of generating and multiplexing seven modes is about 35%. A transmitter for an OAM-based mode-division multiplexing system is proposed based on the discrete Fourier transform between the data carried by the multiple inputs and the data carried by the OAM modes. The experimental implementation of the proposed approach could be achieved by integrating ring fiber, multicore fiber, and photonic integrated circuit technology.
我们提出了一种在具有环形折射率分布的光纤中高效产生和多路复用光学轨道角动量（OAM）模式的方法，方法是使用来自高斯模式的多个相干输入。通过控制多个输入的相位关系，可以有选择地产生不同状态 l 的 OAM 模式。通过控制多个输入的幅度和相位，可以在不增加额外损耗的情况下同时产生多个 OAM 模式。我们通过模拟表明，可以生成模式纯度大于 99%的 OAM 模式（OAM 状态 |l|<3）。产生和多路复用七个模式的功率损耗约为 35%。提出了一种基于多个输入携带的数据与 OAM 模式携带的数据之间的离散傅里叶变换的 OAM 基模式复用系统的发射机。该方法的实验实现可以通过集成环形光纤、多芯光纤和光子集成电路技术来实现。
