GOALI: Polarization Mode Dispersion Compensation in the Spectral Domain Using Liquid Crystal Modulator Arrays

高速光纤通过提供一种高带宽通信手段，在当今的信息技术革命中起着关键的使能作用。商用光传输带宽正以惊人的速度增长。鉴于这些进展，以前被认为微不足道的新效应现在被视为高性能光波系统的关键限制因素。为了维持带宽的增长，需要新技术来补偿随着数据速率的快速增长而出现的新的传输损害。一种叫做偏振模色散（PMD）的效应已经成为限制高速光纤系统传输速率和距离的关键因素。PMD的产生是由于光纤中微小的、空间变化的随机双折射，导致输入和输出偏振态的去相关以及脉冲在时域上的扩散。后一种效应会在数字通信系统中造成误差。这个问题在嵌入式光纤基底中尤其严重，因为许多光纤表现出很强的PMD。本提案描述了一个校企合作项目，该项目旨在展示一种新颖而有利的PMD补偿方法。该概念是利用和扩展在超快光脉冲整形领域发展起来的技术，在计算机控制下逐波长并行补偿宽带光信号的PMD。这改进了目前的方法，这些方法只允许对单一波长的所谓一阶PMD进行补偿，并且不适用于宽带光信号，其中PMD引起的失真在整个光带宽上变化很大。这个研究项目将包括几个方面。一个目标是通过实验来证明所提出的新的PMD补偿方案的有效性。研究还将针对可编程生成的PMD用于测试设备。这两项活动都将得到数值模拟的支持。此外，将设计新的PMD测量策略，以提供适当控制所提出的逐波长PMD补偿器所需的数据。这也将导致适用于多波长系统的偏振状态传感仪器的重大进步。

High-speed fiber optics plays a key enabling role in today's information technology revolution by providing a means for high bandwidth communications. Commercial optical transmission bandwidths are increasing at an impressive rate. In light of these advances, new effects which were previously considered insignificant are now viewed as key limiting factors in high performance lightwave systems. In order to sustain the growth in bandwidth, new technologies are needed to compensate new transmission impairments that arise with rapidly growing data rates. One such impairment, which has become a key factor limiting transmission rates and distances in high-speed fiber systems, is an effect called polarization-mode dispersion (PMD). PMD arises due to small, spatially varying random birefringences in optical fibers, which lead to decorrelation of the input and output polarization states and pulse spreading in the time domain. The latter effect can cause errors in digital communication systems. This problem is especially acute in the embedded fiber base where many fibers exhibit strong PMD. This proposal describes a university-industry collaborative project which aims to demonstrate a novel and advantageous method for compensation of PMD. The concept is to exploit and extend technology developed in the field of ultrafast optical pulse shaping to compensate PMD of wide-band optical signals in parallel on a wavelength-by-wavelength basis and under computer control. This improves on current approaches that only allow compensation of so-called first order PMD for a single wavelength and which do not apply to situations with wide-band optical signals where the distortion caused by PMD varies substantially across the optical bandwidth.This research project will encompass several aspects. One goal is to perform experiments demonstrating the validity of the proposed new PMD compensation scheme. Research will also target programmable generation of PMD for use in test equipment. Both of these activities will be backed up by numerical simulations. Additionally, new PMD measurement strategies will be devised in order to provide the data necessary to suitably control the proposed wavelength-by-wavelength PMD compensators. This should also result in a major advance in instrumentation for state-of-polarization sensing applicable to multiple-wavelength systems.