In this Letter, we experimentally demonstrate beaconless beam displacement tracking for free-space optical communication link multiplexing multiple orbital angular momentum (OAM) beams, where the data-carrying OAM beams are used for position detection. 400 Gbit/s data transmission is demonstrated under emulated lateral displacement of up to $\pm 10\mathrm{mm}$ with power penalties of less than 3 dB for all channels. Channel crosstalk is reduced by the beam tracking system to below $-18\mathrm{dB}$. Moreover, we investigate using a Gaussian beacon for beam displacement tracking, and achieve similar channel crosstalk and power penalties, compared with using the beaconless beam tracking.

中文翻译：

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轨道角动量多路复用自由空间光链路无信标光束位移跟踪的实验演示

在这封信中，我们实验性地证明了自由空间光通信链路复用多个轨道角动量（OAM）光束的无信标光束位移跟踪，其中，数据传输OAM光束用于位置检测。在高达50％的模拟横向位移下演示了400 Gbit / s数据传输$\pm 10\mathrm{毫米}$所有通道的功率损失均小于3 dB。光束跟踪系统将信道串扰降低至低于$-\mathrm{18岁}\mathrm{D\; b}$。此外，与使用无信标波束跟踪相比，我们研究了使用高斯信标进行波束位移跟踪，并获得了相似的信道串扰和功率损失。