Big guns roll onto dwdm battlefield

By GRACE F. MURPHY

Lucent Technologies (Murray Hill, NJ) raised the stakes in the dense wavelength-division multiplexing (dwdm) game when it announced its new system capable of carrying 400 Gbits/sec of traffic per fiber. Then came Pirelli Cables and Systems North America (Lexington, SC) with a system capable of transmitting 160 Gbits/sec over a single optical fiber. Now ciena (Linthicum, MD) is challenging both by saying it can deliver its new 100-Gbit/sec multiplexing system first. In case you haven`t noticed, the siege to capture the potentially huge dwdm market is on--and competing companies are already bringing out the heavy artillery.

Mathew Steinberg, director of optical networking with ryan- hankin-kent (South San Francisco, CA), says systems manufacturers are increasing the size of optical multiplexers in an effort to meet carriers` demand for more bandwidth. "Telecommunications carriers are experiencing fiber exhaust and are looking to dwdm technology for help. The growth over the last three years just continues. All the major carriers and the new entrants are looking at dwdm, and they`re looking at dwdm because it`s a very cost-effective way to add bandwidth. It gives the carrier a lot of flexibility. What we mean by flexibility is to stagger their deployment to help cash flow. That`s real positive for them," Steinberg says.

Not one to pass up an opportunity, Lucent announced in March the Wave- Star ols 400G, a system that will allow users to mix 2.5- and 10-Gbit/sec Synchronous Optical Network and Synchronous Digital Hierarchy (sonet/sdh) streams generated by equipment from multiple vendors. The system accommodates Asynchronous Transfer Mode (atm) and Internet protocol (IP) traffic (see Lightwave, March 1998, page 1). The key to achieving the high bandwidth involves maintaining wavelength integrity within 50-GHz spacing. at&t has said it will test the equipment in its facilities during the fourth quarter of next year, about the same time that Lucent plans to make its Wave-Star ols 400g commercially available.

Meanwhile, Pirelli has announced its WaveMux 6400 system, which is capable of transmitting 64 channels over a single fiber. According to Neal Stoker, Pirelli`s director of marketing, a 32-channel version of Pirelli`s WaveMux 6400 system is on trial in a customer`s lab and could be ordered today. The company expects to be ready to take orders on its "Hyper-Dense Wavelength Division Multiplexing" 64-channel system in the third quarter of 1998, he says.

The WaveMux 6400 platform can be installed as a 4-channel system and upgraded incrementally to 64 channels, as demand requires. The addition of a line extender module allows the configuration of numerous 64-channel systems back-to-back for transmission distance in excess of 8000 km without regeneration. The version of the system released initially will be able to add/drop 12 channels. The system can handle 64 channels of OC-48 (2.5 Gbits/sec) or 16 channels of OC-192 (10 Gbits/sec), or any combination of the two as long as the total rate does not exceed 160 Gbits/sec.

Finally, ciena recently introduced its MultiWave 4000. The system allows a company using 40 channels of OC-48 to deliver 100 Gbits/sec of data over a single fiber and accommodate atm or IP traffic. The unit is scalable to 96 channels, according to the company, which would increase the per-fiber capacity to 240 Gbits/sec.

By using a proprietary technique it calls Wavelock, ciena says it is able to maintain 50-GHz channel spacing within the C band, which is an amount half that of the 100 GHz recommended by the International Telecommunication Union standards. The two keys to Wavelock are, first, locking the frequency of the transmitting lasers so that they stay steady over time and, second, filtering the incoming signals on the receive end of the transmission. In-fiber Bragg gratings developed by the company serve as the enabling technology for this tight filtering, according to Doug Green, CIENA`s director of product marketing, transport products.

The higher-density channel plan leverages the low attenuation of the 1550-nm band. Additionally, wdm transceivers permit the use of standard short-reach OC-48/STM-16 optics to interface with and eliminate the need for sonet/sdh regenerators at back-to-back MultiWave terminal sites.

When introducing the product at February`s Optical Fiber Conference, ciena`s director of marketing, Dennis Bilter, reflected on Lucent`s and Pirelli`s announcements before gesturing at his own display behind him. "The only 50-GHz product available today is sitting right there, it`s just rolled out right now," he said. ciena expects to begin commercial shipments during the second quarter this year.

Steinberg says companies may pre- announce products to indicate a market direction, get a jump on a competitor, or announce their presence in the market. "It also helps when there is a customer with a product. That gives it some validity, that somebody does want the product. There are a whole number of reasons why somebody might go ahead and pre-announce," he says.

While Lucent and Pirelli announced customer trials at the time their systems debuted, ciena may have gotten a jump on the field with its recent announcement that Sprint has purchased the MultiWave 4000 for deployment in its network (see "Sprint commits to dwdm for capacity expansion," page 20).

Meanwhile, other firms are poised to enter the fray. For example, sources at Alcatel Network Systems (Richardson, TX) told Lightwave that their company will unveil a large-capacity system in the middle of this year. q

Stephen Hardy also contributed to this story.