You don't have to go too far back in the history books to find a time when, if you announced to the world that you planned to deploy 1550 nm fiber optic technology, you were considered odd, or unique. After all, 1550 was itself an oddity-a distraction to those who were lobbying cable operators to deploy fiber as fast as possible, but preferred that they use 1310 nm gear.
Just ask Wilt Hildenbrand, vice president of technology at Cablevision Systems. After all, it was he and Al Johnson (now president of Synchronous Communications) who designed and installed perhaps the most extensive 1550 nm cable system in this country. At the time, they were swayed by 1550's ability to be amplified, as well as its lower attenuation, and hence, longer reach into the network. Although he was comfortable with his decision, and it was one that made sense, Hildenbrand was often privately criticized for his actions.
"That's an old wound that has finally healed," Hildenbrand said during an interview earlier this year. Yet he remains mystified why his colleagues reacted the way they did. "There are very few things that have happened in this business that have caused a reaction like that, but this certainly caused a reaction. It caused quite a stir, and I never knew why. To this day, I don't know why. But it doesn't matter to me. To us, it wasn't a case of right or wrong. It worked for us."
But, as is often the case, market forces and product innovation came to 1550's rescue. Perhaps it should come as no surprise that as cable operators have become more familiar and comfortable with fiber optics, that they have also broadened their searches well beyond the obvious for network solutions. But what might surprise many is the rapidity of the resurgence and the number of companies that are now developing products for use at 1550 nm.
Even 1310 evangelist Larry Stark, vice president of new business development at Ortel Corp., has changed his tune. After pronouncing the 1550 approach "dead" in the pages of this magazine several years ago, Stark now says the diagnosis was slightly premature.
"When I made my famous statement, I think it was true at the time," says Stark now. "Our sense was that people were being distracted by too many technologies when 1310 (equipment) was exactly what they needed." Yet Stark understood why Hildenbrand and a few others were intrigued by 1550: "It was a technology that was ahead of its time. People were fascinated by it because it could be optically amplified, but they didn't know how to use it."
But now that many cable systems are actively "clustering" their systems in order to dominate major urban and suburban population areas, they're focused on interconnecting what were once disparate cable systems into a single, large, unified cable network. This approach allows them to collapse headends and share costs across a much wider subscriber base, ultimately saving them money.
In scenarios such as this, 1550 gear plays nicely because of its inherent lower attenuation, its ability to easily amplify signals via the erbium-doped fiber amplifier, and the "broadcast" nature of sending the same signals to several hubsites. Plus, the technology has improved.
In the early days, some companies were using directly modulated distributed feedback lasers to drive 1550 transport systems, which introduced laser chirp and fiber dispersion. Today, most manufacturers have switched to transmitters that feature external modulators and continuous wave lasers to offer video network providers a reliable and cost-effective solution for the interconnect portion of their networks, notes Stark.
International applications are also driving the resurgence in 1550 technology. With limited reason to offer targeted advertising, interactive TV or differentiated programming, many HFC systems being built abroad are interested in one thing: getting video in front of as many eyeballs as possible for as little money as necessary.
Under that scenario, 1550 plays quite nicely, according to Gary Lyons, director of the optoelectronics business unit in Scientific-Atlanta's transmission systems division. "We've done a lot of economic modeling, and it does suggest that if you want the lowest cost method of getting video out, in most cases, it's the 1550 approach," Lyons says. "So if the operator is willing to defer the expenditure for interactivity for three to five years, then 1550 plays very nicely."
John Clark, chief operating officer at ATx, which was recently purchased by Scientific-Atlanta, sums it all up this way: "The model is changing: before, everybody said, `Tell me THE answer for my optical network.' But today there's a richer toolkit that never existed before, so the answer depends on who you are, where you are, the money you have to spend and the services you want to offer."
"There's been a heck of a lot of 1550 gear put in over the last two years or so," notes John Dahlquist, vice president of marketing at Harmonic Lightwaves. And now that his company is about to begin shipping 1550 equipment, he hopes the trend continues.
He suspects it will, driven by operators who need to interconnect networks, collapse headends and want broad pipelines for high-speed Internet access, video-on-demand applications and similar new, bandwidth-hungry applications. "The digital (set-tops) should also be out soon, which will drive this need even more," Dahlquist argues.