Opt Lett. 2019 Jan 15;44(2):255-258. doi: 10.1364/OL.44.000255.
An optically controlled system for generating and continuously steering radio frequency (RF) signals with double orbital angular momentum (OAM) modes is proposed and experimentally demonstrated. The optical carrier's utilization efficiency can be doubled through the distinct electro-optical modulation, which is based on two single-sideband modulation operations on a single optical carrier through a customized dual-parallel Mach-Zehnder modulator. A constructive antenna phase feeding method of a circular antenna array for collectively forming and steering an OAM radio beam is proposed and illustrated. A proof-of-concept experiment is conducted to generate and steer a dual-mode RF-OAM beam to two different two-dimensional (2D) directions, independently and simultaneously. One 17 GHz OAM beam with mode L=1 is continuously steered to 2D directions (:, 0°, 0°), (:, 0°, 1.70°), (:, 0°, 3.87°), (:, 0°, 6.17°), and(:, 0°, 7.80°), with vortex properties, where ":" means "any value of." Meanwhile, the 19 GHz OAM beam with mode L=-1 carried is steered from (:, 0°, 0°) to (:, 0°, -6.72°), and the constellations are obtained successfully.
提出并实验演示了一种用于产生和连续转向射频（RF）信号的光控系统，该系统具有双轨道角动量（OAM）模式。通过独特的电光调制，可以将光载波的利用率提高一倍，该调制基于通过定制的双平行马赫-曾德尔调制器对单个光载波进行两个单边带调制操作。提出并说明了一种圆形天线阵列的建设性天线相位馈电方法，用于集体形成和转向 OAM 无线电波束。进行了一项概念验证实验，以产生和转向双模式 RF-OAM 波束到两个不同的二维（2D）方向，独立且同时。一个 17 GHz 的 OAM 模式 L=1 的波束以涡旋特性被连续转向到 2D 方向（：，0°，0°）、（：，0°，1.70°）、（：，0°，3.87°）、（：，0°，6.17°）和（：，0°，7.80°），其中“：”表示“任何值”。同时，承载的 19 GHz OAM 模式 L=-1 的波束从（：，0°，0°）转向（：，0°，-6.72°），并成功获得了星座。
