Spatial Multiplexing in Multimode Fiber using Adaptive Optical or Digital Signal Processing

本研究的目的是发展增加短距离和长距离光纤网络传输容量的技术。该方法是在多模光纤中使用空间复用，这是一种多输入、多输出的传输形式。智能优势：短距离光纤系统，如数据中心和局域网，已经使用了具有直接检测功能的多模光纤，但受模态色散的限制，每根光纤只能达到10gbit /s。自适应光信号处理将用于在这些系统中防止模态色散和实现空间复用。本项目开发的方法将同时克服模态色散，并在直接探测系统中实现成倍的容量增益。较长距离的系统目前使用单模光纤，现在使用相干检测，它保留了光信号的相位和偏振信息。将开发自适应数字信号处理技术来补偿模态色散和实现空间复用。与模式相关的光纤损耗和放大器增益会导致信号衰落，就像在无线系统中一样。系统级方法，如模态频率分集和空时编码，将在不显著牺牲多路复用增益的情况下确保可靠性。将研究基本分集与多路复用的权衡。更广泛的影响：该项目将使光传输容量大幅增加，并有助于降低每比特成本，有利于研究、教育、医疗保健、商业和安全。将启用多模媒体的新应用，以补充单模媒体。光通信和无线通信之间将建立新的联系，这将激励这两个领域的工程师。高中生将接触到最新的研究成果。来自不同背景的本科生和研究生将接受研究培训。研究结果将纳入本科和研究生课程。

The objective of this research is to develop techniques for increasing transmission capacity in both short-reach and long-reach fiber networks. The approach is to use spatial multiplexing in multimode fiber, which is a form of multi-input, multi-output transmission.Intellectual Merit: Short-reach fiber systems, such as data-center and local-area networks, already use multimode fiber with direct detection, but are limited by modal dispersion to only 10 Gbit/s per fiber. Adaptive optical signal processing will be used to prevent modal dispersion and enable spatial multiplexing in these systems. The approach developed in this project will simultaneously overcome modal dispersion and achieve multiplicative capacity gains in direct-detection systems. Longer-reach systems currently use single-mode fiber, and are now using coherent detection, which preserves information on phase and polarization of optical signals. Adaptive digital signal processing techniques will be developed to compensate modal dispersion and enable spatial multiplexing. Mode-dependent fiber losses and amplifier gains can cause signal fading, as in wireless systems. System-level approaches, such as modal-frequency diversity and space-time coding, will ensure reliability without significantly sacrificing multiplexing gain. Fundamental diversity-multiplexing tradeoffs will be studied.Broader Impacts: This project will enable dramatic increases in optical transmission capacity, and will help lower the cost per bit, benefiting research, education, healthcare, commerce, and security. New applications of multimode media will be enabled, complementing single-mode media. New connections between optical and wireless communications will be made, inspiring engineers in both fields. High-school students will be exposed to current research. Undergraduate and graduate students from diverse backgrounds will receive research training. Results of research will be integrated into undergraduate and graduate curricula.