ITTC Project

Modeling Ultra-Dense, Ultra-High Speed WDM Fiber Networks

Project Award Date: 01-01-2002


The rapid evolution of WDM terminal equipment presents unprecedented challenges to network planners. This is because the overall performance of these ultra-dense, ultra-high-speed WDM systems may depend very heavily on the distribution of the fiber parameters throughout the link. Because of the small performance margins of these systems, small changes in link parameters (such as amplifier spacings) could lead to catastrophic system performance. Although it is theoretically possible to predict system performance using experimental results, such experiments are costly, time consuming, and prone to error. A more attractive way to predict the system performance of high-speed, dense WDM fiber networks is using numerical modeling. Such models can be used to determine the performance envelopes of networks, since a wide range of network parameters can be changed easily.

The KU/ITTC Lightwave Communication Systems Laboratory has been developing fiber modeling software for a number of years. The majority of this effort has been towards developing a full-wave capability for WDM systems. The first codes were designed for small numbers of wavelengths as a research tool, in order to study various fiber transmission anomaly. Like most other present-generation modeling codes, this code was limited in terms of numbers of wavelengths and bit-rates.

Most recently, a robust version of this code has been developed that is capable of modeling larger systems with greater numerical and user flexibility. This code is capable of modeling WDM networks with hundreds of optical carriers at data rates of upwards of 40 GB/s and can be used on both Windows and Alpha computing platforms. All of the major fiber signal degradation mechanisms are included in this model, including self- and cross-phase modulation, first- and second-order dispersion, loss, Raman scattering, four-wave mixing (FWM), modulation instability, birefringence, and polarization mode dispersion. An alpha version of this code was delivered to Sprint in early 2001.

The goal of this new effort is to expand the functionality and operability of this code, to rigorously test it, and to use it to model dense WDM situations of interest to Sprint TP&I. The functionality and operability of the code will be expanded to allow the greatest possible flexibility in modeling the widest possible range of WDM networks with the least possible operator expertise. We will work closely with Sprint TP&I as they evaluate the alpha version of the code. We will also continue to increase the number and range of the devices and system options available to the modeler.

The code has already undergone extensive testing for numerical accuracy, and this process will continue throughout the next phase of this work. This testing is essential, since the performance margins of dense WDM networks are generally so slim. In addition, an exact knowledge of the performance envelope of this code is needed in order to make it as numerically efficient as possible, which will allow it to model the largest possible WDM networks.

Throughout this effort, we will use the code to model the performance of various network configurations of interest to TP&I. With this in mind, we will enable the code to model the performance of higher-level modulation schemes in a WDM environment. In particular, we will model QPSK modulation for 10Gbps streams and compare this against Prof. Ron Hui's SCM scheme, all in the C band.


Faculty Investigator(s): Kenneth Demarest (PI), Rongqing Hui, Christopher Allen

Student Investigator(s): Minnan Fei, Chidambaram Pavanasam

Project Sponsors

Primary Sponsor(s): Sprint

Partner with ITTC

The Information and Telecommunication Technology Center at the University of Kansas has developed several assistance policies that enhance interactions between the Center and local, Kansas, or national companies. 

ITTC assistance includes initial free consulting (normally one to five hours). If additional support is needed, ITTC will offer one of the following approaches: 

Sponsored Research Agreement

Individuals and organizations can enter into agreements with KUCR/ITTC and provide funds for sponsored research to be performed at ITTC with the assistance of faculty, staff and students.

Licensing and Royalty/Equity Agreement

An ITTC goal is the development of investment-grade technologies for transfer to, and marketing by, local, Kansas, and national businesses. To enhance this process, the Center has developed flexible policies that allow for licensing, royalty, and equity arrangements to meet both the needs of ITTC and the company.

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Companies with a technology need that can be satisfied with ITTC's resources can look to us for assistance. We can develop a relationship with interested partners that will provide for the development of a technology suited for commercialization.

ITTC Resource Access

ITTC resources, including computers and software systems, may be made available to Kansas companies in accordance with the Center's mission and applicable Regents and University policies.

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