CAREER: Optimizing Fiber-Optic Communication Systems Through Analytical Modeling of Linear and Nonlinear Signal Degradations

这项研究致力于多用户光通信系统的设计和分析，以提高现有和未来系统的性能、距离和容量。重点放在物理层，即连接大型节点的实际单光纤链路。对进出每个家庭和办公室的更多数据、语音和视频的强烈需求导致了通常是宽带和高功率的多用户系统，有时由于光纤固有的特性导致信号严重的线性和非线性退化。掌握这些物理限制可以转化为现有基础设施的容量增加100到1000倍，潜在节省数十亿美元。该研究项目的目标是识别、表征和对抗光纤中的信号衰减，并利用这些信息来设计最大容量的多用户系统。虽然光纤的物理特性已经被广泛地测量和定义，但光纤系统的适当设计以优化通信的信号特性还没有被充分考虑。已经开发了一种工具，该工具提供了一种获得描述光信号通过石英光纤传输的非线性微分方程解的解析封闭形式的方法。其结果是光纤的Volterra模型，该模型既可用于量化光纤引起的信号退化，也可用于设计算法和设备来对抗这种影响。该模型将用于分析光TDMA、CDMA和WDMA网络的性能，包括实际失真，如互调产物、码间干扰和多用户干扰。然后，这个相同的模型将被用来定义信号处理算法和相应的非线性装置，以对抗信号退化。将研究在多用户系统中创建使用孤子波形的通信系统的可能性。孤子是非常理想的，因为它们利用非线性光纤效应来抵消由线性效应引起的脉冲色散。最后，通过对Volterra模型的修正，分析了非线性偏振等对相干光通信系统的影响。这项研究的教育部分包括三门新课程，旨在改善弗吉尼亚大学本科生和研究生在光通信和多用户通信方面的教学。两门课程强调从头开始开发光通信系统(不依赖于通常的射频模拟)，第三门课程强调多用户通信，与本课程和相关研究直接相关。一所教育机构只有满足当前和未来学生的需求，才能实现为未来的新一代做好准备的主要目标。这一目标的一个重要方面是回应妇女对工程领域日益增长的兴趣。根据她的假设，女性被社会化是为了在人类和社会关注的问题上找到重要性，这位研究人员将积极修改当前的工程教学方法，以展示技术方法论与由此产生的产品和服务之间的联系。将鼓励学生在与工作场所环境相呼应的明确定义的小组中工作。在一个正在从男性主导转型的领域里，作为一名女性，肩负着成为榜样的责任。工程专业的女学生将被特别鼓励参加一项旨在促进成功、归属感和强烈自尊的指导计划。万维网链接：http://watt.seas.Virginia.EDU/~mb9q/

This research pursues the design and analysis of multiuser optical communication systems to increase the performance, distance, and capacity of existing and future systems. The focus is on the physical layer - i.e., the actual single fiber links that connect the nodes of large. The intense demand for more data, voice, and video in and out of every home and office has led to multiuser systems that are typically broadband and high power, sometimes leading to severe linear and nonlinear degradation in the signal due to properties inherent to the fiber. Mastering these physical limitations can translate into a hundred to thousand fold increase in capacity of existing infrastructure, with a potential savings of billions of dollars. The goal of this research project is to identify, characterize, and combat signal degradation in fibers, and to use this information to design the highest capacity multiuser systems. While the physical properties of fibers have been broadly measured and defined, the proper design of fiber systems to optimize signal properties for communications has not been fully considered. A tool has been developed that provides a method of obtaining an analytical closed-form solution of a nonlinear differential equation describing the propagation of optical signals through silica fiber. The result is a Volterra model for the fiber which can be used to both quantify the signal degradation due to the fiber and to design algorithms and devices to combat this effect. The model will be used to analyze the performance of optical TDMA, CDMA, and WDMA networks including realistic distortions such as intermodulation products, intersymbol interference, and multiple user interference. This same model will then be used to define signal processing algorithms and corresponding nonlinear devices to combat signal degradation. The possibility of creating a communication system that uses the soliton waveform in multiuser systems will be studied. Solitons are hi ghly desirable in that they take advantage of the nonlinear fiber effects to cancel pulse dispersion caused by linear effects. Finally, effects such as nonlinear polarization on coherent light communication systems will be analyzed using a modification of our Volterra model. The education portion of this study includes three new courses for improving the instruction of undergraduates and graduates in optical communications and multiuser communication at the University of Virginia. Two courses emphasize development of the optical communication system from the ground up (without relying on the usual RF analog), followed by a third course in multiuser communication, tied directly to this and related research. The primary goal of an educational institution to prepare the new generations for tomorrow can be accomplished only if the institution responds to the needs of the current and future students. One important aspect of this goal is to respond to the increased interest of women in the field of engineering. Following her hypothesis that women are socialized to find importance in issues of human and social concern, this researcher will be active in modifying the current methods of teaching engineering to show the link between technical methodology and the resulting products and services. Students will be encouraged to work within well defined groups that echo the work place environment. Being a female in a field that is in transition from being male dominated carries the responsibility of being a role model. Female engineering students will be especially encouraged to participate in a mentoring program instituted to promote success, a sense of belonging and strong self esteem. World-Wide Web Link: http://watt.seas.Virginia.EDU/~mb9q/