Martin Zirngibl

WDM cross-connect architectures with reduced complexity

With the arrival of wavelength division multiplexed (WDM) systems carrying large numbers of wavelength channels, it appears that new cross-connect architectures that allow large numbers of wavelength channels to cross-connect at the wavelength granularity level are required. We propose a number of such architectures. The different architectures are compared in terms of complexity, cost, loss, crosstalk and filter narrowing. An analysis of the various nonblocking properties of such cross-connects is also described.

Mode stabilization technique for the multifrequency laser

A mode stabilization technique for waveguide grating router lasers which allows suppression of multi-longitudinal mode operation while simultaneously decreasing the laser chip size and increasing the maximum modulation speed is described.

Applications for Optical Switch Fabrics

The explosion in bandwidth demand over the backbone network has led to a bottleneck in switching information. Indeed, the capacity of fiber transmission lines has been growing at a much faster rate over the past few years than the throughput capacity of switching nodes. Commercially available fiber transmission systems now carry more than 1 Tb/s of information per fiber. The largest electronic cross-connects have barely reached 1 Tb/s of total throughput. Now imagine 10 optical fibers terminating in a switching node and each one carrying eventually 1 Tb/s or more traffic. It is easy to see that switching nodes with at least 10 Tb/s throughput capacity are needed in order to handle this type of fiber capacities.

Demonstration of a 1252-subscriber WDM access PON architecture using a single sequentially pulsed multifrequency laser WDM source

In summary, a new WDM passive optical network (PON) architecture was shown capable of supporting 144 eight-channel WDM access PONs for a total of 1152 subscribers, each having 53-Mbit/s downstream capacity. This scalable PON architecture shares the source cost among a large number of subscribers and allows flexible capacity upgrading or provisioning.

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

Next generation packet routers

Current IP/ATM routers use an electrical switching fabric/backplane and either optical or electrical interconnects between the line cards to route data. An electrical backplane and associated connectors limit the number of high speed interconnections due to practical considerations. Scaling these so-called third generation routers to the terabit regime with high port densities faces enormous problems due to the high interconnect and electrical power density. Packet routers with an optical switching fabric are considered as the next generation of IP/ATM Multi-Service routers which enable scalability towards the Terabit and Petabit regime. In this paper, various architectures with electrically active or passive optical switch fabrics will be highlighted and differences in terms of switching speed and scalability will be discussed. Recent results using a passive Array Waveguide Grating (AWG) router and fast wavelength tunable laser are presented in the second half of this paper.

A splitter/router based on a chirped waveguide grating router

We propose and demonstrate a novel method to build a device that acts like an optical multiplexer in one wavelength band and an optical power splitter in another one. The method is based on a chirped waveguide grating router design. There is no penalty in terms of insertion loss or crosstalk for the routing characteristics of the device but there is a tradeoff between the splitter bandwidth and the splitter excess loss. The simulated and experimental results are in good qualitative agreement.

Demonstration of the MFL temperature tracking capability in a 12/spl times/155 Mb/s WDM PON

The goal of this paper is to demonstrate a WDM passive optical network (PON) with components that have the functionality to be used in access systems. Outside plant conditions were simulated by changing the temperature of the passive remote node (RN) demultiplexer, in our case the waveguide grating router.