Steven K. Korotky

Analytical description of shared restoration capacity for mesh networks

We derive analytical expressions for the extra capacity requirements of mesh networks to ensure survivability against single-link failures. We study both shared link- and path-based restoration schemes and formulate the network global expectation value of extra capacity. We analyze a wide range of planar and toroid mesh networks using a linear programming optimization tool and find our analytic model in good agreement with the numerical simulation data.

Optical Switching in Transport Networks: Applications, Requirements, Architectures, Technologies, and Solutions

Publisher Summary Early Dense Wavelength Division Multiplexing (DWDM) optical line systems provided simple point-to-point links between electronic end terminals without allowing access to the intermediate wavelength channels. It is noted that todays systems carry over 100 channels per fiber and new technologies allow intermediate routing of wavelengths at add or drop multiplexers and optical cross-connects. Thus, these new capabilities allow optical layer networking, which is essentially architecture with great flexibility and intelligence. The use of optical switching in modern networking architectures has been explored in the chapter. It reviews the principles of networking and various aspects of optical switch technologies in detail. The performance and requirements for an Optical Cross Connect (OXC) for opaque and transparent technologies are also compared. Furthermore, the chapter reviews the applications of OXC in areas such as provisioning, protection, and restoration. Several demonstration OXCs are also studied, including small optical switch fabrics, wavelength–selective OXCs, and large strictly nonblocking cross connects employing the Microelectromechanical System (MEMS) technology.

Analysis and optimization of two-tier networks with application to opticaltransport backbones

Communication networks are often partitioned into tiers to provide a convenient framework for their optimization, graceful growth, and evolution. We extend the application of the Network Global Expectation model, which we have recently described, by considering a two-tier architecture for a communication network and analyzing the corresponding network requirements and costs using expectation values evaluated over the entire network. We also explicitly treat nonuniform traffic in the form of population-dependent demand. The capability of the model is illustrated by demonstrating scenarios for which the two-tier architecture may be used to reduce the cost of an optical fiber backbone network relative to a single-tier solution.

Scaling of Most-Likely Traffic Patterns of Hose- and Cost-Constrained Ring and Mesh Networks

We report analytical results and statistical comparisons for the solution to the hose- and cost-constrained inverse problem for the traffic matrix and distance-dependence of ring and mesh networks based on the method of maximum entropy.

Loss-less bridging in 1+1 optical protection using a modified transmitter and receiver

Traditional 1+1 optical layer protection is implemented by creating two signals from one via a 3-dB splitter (with /spl sim/3-dB insertion loss) and transmitting both signals along two different path-diverse optical fibers. In this letter, a transmitter has been modified to provide two signals in such a manner that no excess insertion loss is encountered. Optical protection switching using this transmitter and a modified invertible receiver is demonstrated under 10-Gb/s nonreturn-to-zero transmission. A protection time of 5 ms is obtained.

Insertion loss model and input/output losses of single-stage optical cross-connects

We propose and demonstrate an effective model of the insertion loss of single-stage optical cross-connects, which has application to improve the speed and quality of connection training, to reduce the size of the loss table, and to facilitate maintenance.

Call for Papers: Convergence

Call for Papers: Convergence Guest Editors: Thomas E. Darcie, University of Victoria Robert Doverspike, AT&T Martin Zirngibl, Lucent Technologies Coordinating Associate Editor: Steven K. Korotky, Lucent Technologies Submission Deadline: 1 January 2006 The Journal of Optical Networking (JON) invites submissions to a special issue on Convergence. Convergence has become a popular theme in telecommunications, one that has broad implications across all segments of the industry. Continual evolution of technology and applications continues to erase lines between traditionally separate lines of business, with dramatic consequences for vendors, service providers, and consumers. Spectacular advances in all layers of optical networking-leading to abundant, dynamic, cost-effective, and reliable wide-area and local-area connections-have been essential drivers of this evolution. As services and networks continue to evolve towards some notion of convergence, the continued role of optical networks must be explored. One vision of convergence renders all information in a common packet (especially IP) format. This vision is driven by the proliferation of data services. For example, time-division multiplexed (TDM) voice becomes VoIP. Analog cable-television signals become MPEG bits streamed to digital set-top boxes. T1 or OC-N private lines migrate to Ethernet virtual private networks (VPNs). All these packets coexist peacefully within a single packet-routing methodology built on an optical transport layer that combines the flexibility and cost of data networks with telecom-grade reliability. While this vision is appealing in its simplicity and shared widely, specifics of implementation raise many challenges and differences of opinion. For example, many seek to expand the role of Ethernet in these transport networks, while massive efforts are underway to make traditional TDM networks more data friendly within an evolved but backward-compatible SDH/SONET (synchronous digital hierarchy and synchronous optical network) multiplexing hierarchy. From this common underlying theme follow many specific instantiations. Examples include the convergence at the physical, logical, and operational levels of voice and data, video and data, private-line and virtual private-line, fixed and mobile, and local and long-haul services. These trends have many consequences for consumers, vendors, and carriers. Faced with large volumes of low-margin data traffic mixed with traditional voice services, the need for capital conservation and operational efficiency drives carriers away from todays separate overlay networks for each service and towards

Optical communication transport and networking: trends, technology challenges, and opportunities

Summary form only given. The authors research team is responsible for the identification, assessment, feasibility prototyping, and early development of new technology critical for metropolitan and long distance networks. These networks include high-capacity, ultralong-haul WDM optical line systems, optical add/drop multiplexers, optical cross-connects, and distributed mesh operation systems. The author best known for researching, developing, and introducing external modulation and pulse generation into high-speed fiber transmission systems deployed worldwide.