Chou Hsi-Hsir, Liu Kang-Yun
Opt Lett. 2021 Nov 1;46(21):5381-5384. doi: 10.1364/OL.431558.
An asymmetric bidirectional visible light communication (B-VLC) system is presented in this Letter. It combines beam homogenizers with a spatial light modulator (SLM) to implement the orbital angular momentum (OAM) generation technology at a terminal user for uplink data transmission. The major advantage of the proposed approach is that multiple OAM modes can be arbitrarily generated simultaneously by a single SLM. The uplink transmission capacity can also be significantly improved by multiplexing more generated OAM channels. For the proof of concept, an asymmetric B-VLC based on the OAM generation technology for uplink transmission at a distance of nearly 2 m has been implemented. The baseband modulation schemes, including on-off keying (OOK) and quadrature phase-shift keying, were also implemented to validate the transmission performance. The experimental results show that the downlink transmission capacity of up to 2.2 Gbit/s can be achieved using an -polarization beam. In comparison, the uplink transmission capacity can also be significantly enhanced by using -polarization through multiplexing four OAM channels, each with a maximum transmission rate of up to 800 Mbit/s. The bit error rates (BERs) of both uplink and downlink transmissions were all under the forward error correction limit (=3×10).
本文提出了一种非对称双向可见光通信（B-VLC）系统。它将光束均匀器与空间光调制器（SLM）相结合，在终端用户处实现轨道角动量（OAM）生成技术以进行上行数据传输。该方法的主要优点是单个SLM可同时任意生成多个OAM模式。通过复用更多生成的OAM信道，上行传输容量也可显著提高。为了验证概念，已实现了一种基于OAM生成技术的非对称B-VLC，用于近2米距离的上行传输。还实现了包括开关键控（OOK）和正交相移键控在内的基带调制方案，以验证传输性能。实验结果表明，使用 - 偏振光束可实现高达2.2 Gbit/s的下行传输容量。相比之下，通过复用四个OAM信道（每个信道的最大传输速率高达800 Mbit/s），使用 - 偏振也可显著提高上行传输容量。上行和下行传输的误码率均在前向纠错极限（=3×10）以下。
