Lucent outlines optical technology efforts
STEPHEN HARDY
Buoyed by expectations that the market for Synchronous Optical Network (Sonet) equipment could exceed $4.5 billion by 1999, Lucent Technologies, Holmdel, NJ, has unveiled an aggressive strategy for new product development founded on wavelength-division multiplexing (wdm) and optical networking technology. The future, according to Lucent staffers, will see Sonet remain a key technology, but primarily in the context of a layered network management architecture. Meanwhile, wdm will quickly find application in metropolitan networks, paving the way for new voice, data, and video services.
In a meeting with Lightwave staff, several key members of Lucent`s Sonet team outlined the company`s present and future Sonet product offerings. They also revealed much of the philosophy that will drive Lucent`s technology development efforts. For example, Dawn Hogh, assistant vice president for Sonet market development, said that Sonet remains well-suited to meet users` ever-increasing needs for bandwidth. Its status as what Hogh described as "the only standard" for high-speed, long-distance communication and its secure place in Asynchronous Transfer Mode (atm) specifications should enable it to maintain an important role in future network plans. This should remain the case even if radical network changes--such as the use of the Internet as a major telecommunications backbone--should occur. The $4.5 billion future market estimate underscores this belief. Hogh said the company foresees that nearly $1.3 billion of this figure will comprise digital crossconnect systems, with Sonet transport equipment accounting for the rest of the demand.
As users look to expand the capacity of their Sonet plant, Hogh said that both wdm and time-division multiplexing technologies such as 10-Gbit/sec OC-192 will receive attention. Lucent sees both approaches as viable, depending upon such factors as current and long-term bandwidth needs, life-cycle cost analyses, fiber plant capabilities, and proprietary business considerations. In this context, Sonet will be used with atm technology. Lucent sees this pairing evolving in a layered bandwidth management approach, with atm appearing "inside Sonet" for integration with existing Sonet infrastructures and over other types of optical networks for new applications that do not require Sonet capabilities. The Sonet/atm layer would be sandwiched between application and photonic transport/network layers. The goal, Hogh said, would be an all-optical network that would provide essentially limitless bandwidth and service-independent transport under a unified network management architecture.
Addressing in more detail the envisioned mix of wdm and OC-192 for future applications, Bell Laboratories fellow and technical manager for optical technology development Stan Lumish indicated that cost/benefit analyses of the use of dense wdm (dwdm) versus OC-192 in applications where the amount of fiber is constrained established a "gray area" where a case could be made for either technology (see figure). When users have the option of laying additional fiber, overlay networks were most cost-effective in applications requiring less than 60-km spacing.
Lumish said that Lucent had directed its research toward making dwdm more cost-effective at node spacings of less than 60 km. By combining wdm with optical line system products, Lucent sees wdm appearing quickly in metropolitan network applications that mix 2.5-Gbit/sec OC-48, 622-Mbit/sec OC-12, and 155-Mbit/sec OC-3 signals. Lumish described potential applications that involved leasing wavelengths to several customers using the same fiber, the evolving introduction of atm on embedded plant to allow the use of one network infrastructure for multiple services, and various video and multimedia service offerings.
Both Hogh and Lumish detailed current and future product offerings in Sonet and optical networking, respectively. Hogh said Lucent will base its future Sonet offerings on a single hardware/software bandwidth management platform. This platform will evolve into three product families: an stm/atm business access system, a nodal bandwidth management system, and a high-speed transport system. An integrated network management platform will control these systems through the central office.
Lucent expects to release several new products in 1997 toward this goal, Hogh said. These include a long-span dwdm system with fixed-wavelength add/drop capabilities, a 16-wavelength dwdm system, dwdm optimized for metropolitan applications, and dwdm network management. Next year will see the introduction of "next-generation" OC-48 products that will be upgradable to OC-192, the nodal bandwidth manager, a Sonet/atm multiplexer (part of the stm/atm business access system family), and improved network management products.
On the optical networking side, Lumish foreshadowed several improvements to the company`s optical line system. These included the addition of 16-wavelength capability, effective over eight spans with an attenuation of 24 dB per span; optimization of the system to support both long-haul and metropolitan applications; optical interfaces for both OC-3 and OC-12; and wavelength add/drop abilities with optical translator units for OC-3, OC-12, and OC-48. Lumish said these enhancements should appear in the second half of this year. Looking to 1998, Lucent expects to release a 16-wavelength capability effective over three spans with 33-dB attenuation per span, programmable wavelength add/drop, enhanced operations integration for the optical translator units, network self-identification, and optical monitoring.
In summarizing their presentations, the Lucent spokespersons emphasized that marketing and technology trends point toward the eventual development and deployment of all-optical networks--and that wdm will play an important role in this evolution. q