Ultra-High-Capacity Optical Communications and Networking: Data processing modules using high-nonlinearity fiber for advanced optical networking

超高容量光通信和网络：使用高非线性光纤实现先进光网络的数据处理模块

• 批准号: 0123495
• 负责人: Prem Kumar
• 金额: $ 35万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-10-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0123495&HistoricalAwards=false
• 关键词: Ultra; Capacity; Optical; Communications; Networking

The high demand likely to be placed on the capacity of telecommunication networks in the near future urgesconversion of hybrid electro-optical signal processing to all-optical processing, exploiting the largest bandwidth available in the optical domain. One way of catering to this demand is by multiplexing in time aswell as wavelength domains. Using picosecond-duration optical pulses, which could be soliton-like overportions of the network, one can first perform multiplexing in the time domain (i.e., time-division multiplexing, or TDM) for local to metropolitan-area network applications and then in the wavelength domain (wavelength-division multiplexing, or WDM) for wide area coverage. This scenario leads one to conclude that the key issue to be addressed is how to take advantage of the powerful digital-processing techniques in the pure-optical domain, that minimize the detrimental effects of noise at a very fundamental level. The idea is that, for digitally encoded data [1's (0's) represented by the presence (absence) of pulses], instead of using linear amplifiers which act on signals in an analog fashion and inevitably introduce 3 dB of noise one can employ digital-switching amplifiers or optical regenerators. At the same time, pure-optical digital switching is potentially much more reliable and faster than electro-optical switching. Furthermore, optical switching will also be needed to implement other networking functions, such as demultiplexing to process at very high speed the header of a data packet used for addressing to different users on the network. Our preliminary experiments show that the parametric nonlinearity of optical fibers can be exploitedto perform functionalities that will be needed in packet-switched all-optical networks, such as fiber-opticcache-memory buffers, picosecond-pulse all-optical regenerators, all-optical limiters, and tunable clock re-covery modules. These devices take advantage of the ultrafast parametric nonlinearity of glass fiber andhence are capable of operating at speeds in excess of 100 Gb/s. Moreover, they will be essential for deployingpacket-switched, ultrahigh-speed time-division and wavelength-division multiplexed all-optical networks. In all of our experiments thus far, standard dispersion-shifted fiber (DSF) has been used. Fiber lengthson the order of 100's of meters are required for used with ps-duration pulses of a few watts peak power toachieve the data processing functions. Here we propose to explore the use of high-nonlinearity fiber, suchas microstructure fiber (MF, which is only now becoming commercially available), to perform essentialfunctions in high-speed all-optical processing. Because of their strongly guiding behavior, the MFs canbe wound into very tight loops, suggesting that they could potentially fit into a compact modular switchingpackage. Specifically, we propose to utilize the high-nonlinearity microstructure fibers to develop all-optical data processing modules. These include a cache storage buffer based upon parametric amplification that will be capable of operating in the 10's of Gb/s range. With use of the high-nonlinearity fiber, the average pump power requirement can be met with commercially-available watt-class optical amplifiers. We will carry out experiments to explore various ways of reading, writing, and erasing the stored data patterns.Our work has shown that the ultrafast parametric nonlinearity can be exploited either to provide broadbandtunable gain or dynamic gain modulation for clock-recovery. We propose to combine the two to demonstrateoptical phase-lock loops, which in principle can be extremely fast as they rely on the Kerr nonlinearityfor envelope-phase discrimination. Simultaneous to the above experimental studies we will also developnumerical models of the various optical systems. This will provide a design tool to determine the parametervalues allowing the most efficient operation of the experimental setups. We have previously demonstratedthe possibility of stably propagating sub-picosecond pulses in fiber lines in which conjugating gain is usedto compensate the linear loss. We propose to assemble a re-circulating loop experiment in which linear losswill be compensated by a pair of non-degenerate parametric (conjugating) amplifiers. The location of thetwo amplifiers will be chosen based upon further theoretical/numerical results. We will experimentally andtheoretically study the stability properties of the sub-picosecond pulses by making various signal and noisemeasurements, and will compare the experimental results directly with numerical simulations.

在不久的将来，对电信网络容量的高需求可能促使混合电光信号处理向全光处理的转变，利用光域最大的可用带宽。满足这种需求的一种方法是在时间和波长域上进行多路复用。使用皮秒持续时间的光脉冲，它可能是网络的孤立部分，可以首先在时域（即时分多路复用，或TDM）执行多路复用，用于本地到城域网应用，然后在波长域（波分多路复用，或WDM）进行广域覆盖。这种情况使人们得出结论，需要解决的关键问题是如何利用纯光领域强大的数字处理技术，从而在非常基本的水平上最小化噪声的有害影响。这个想法是，对于数字编码数据[由脉冲存在（不存在）表示的1(0)]，而不是使用以模拟方式作用于信号的线性放大器，并且不可避免地引入3db的噪声，可以使用数字开关放大器或光学再生器。同时，纯光数字交换可能比电光交换更可靠和更快。此外，光交换还需要实现其他网络功能，例如解复用，以便以非常高的速度处理用于网络上不同用户寻址的数据包的报头。我们的初步实验表明，可以利用光纤的参数非线性来执行分组交换全光网络中所需的功能，例如光纤缓存存储器缓冲器，皮秒脉冲全光再生器，全光限制器和可调谐时钟恢复模块。这些器件利用了玻璃纤维的超快参数非线性，因此能够以超过100 Gb/s的速度运行。此外，它们对于部署分组交换、超高速时分和波分多路全光网络至关重要。到目前为止，我们所有的实验都使用了标准色散位移光纤（DSF）。使用峰值功率为几瓦、持续时间为ps的脉冲来实现数据处理功能，需要光纤长度在100米左右。在这里，我们建议探索使用高非线性光纤，如微结构光纤（MF，现在才开始商业化），以执行高速全光处理的基本功能。由于其强烈的引导行为，MFs可以缠绕成非常紧密的环路，这表明它们可能适合紧凑的模块化开关封装。具体来说，我们提出利用高非线性微结构光纤来开发全光数据处理模块。其中包括一个基于参数放大的缓存存储缓冲器，它将能够在10gb /s范围内运行。使用高非线性光纤，平均泵浦功率要求可以满足市售瓦级光放大器。我们将开展实验，探索各种读、写、擦除存储数据模式的方法。我们的工作表明，超快参数非线性既可以提供宽带可调增益，也可以用于时钟恢复的动态增益调制。我们建议结合两者来演示光学锁相环，原则上可以非常快，因为它们依赖于克尔非线性的包络相位鉴别。在进行上述实验研究的同时，我们还将开发各种光学系统的数值模型。这将提供一个设计工具来确定参数值，从而使实验装置最有效地运行。我们以前已经证明了在光纤线路中稳定传播亚皮秒脉冲的可能性，其中使用共轭增益来补偿线性损耗。我们建议组装一个再循环环路实验，其中线性损耗将由一对非退化参数（共轭）放大器补偿。两个放大器的位置将根据进一步的理论/数值结果来选择。我们将从实验和理论上研究亚皮秒脉冲的稳定性，通过各种信号和噪声测量，并将实验结果直接与数值模拟进行比较。