Cable operators will be introduced to a new over-the-air
multiple-wavelength optical system from Lucent Technologies this week that could ease
industry expansion into high-definition television and business services.
Lucent has been working on an iteration of its new
"OpticAir" system specifically for use in cable, officials said. They declined
to go into detail, but it appeared that the application would be aimed at providing
transport support for bandwidth-consuming HDTV signals.
Possibly more significant, the new technology has major
potential for anyone seeking to deliver high-bandwidth services to the business sector,
insofar as it offers a low-cost optical connection from a fiber-ring network, for example,
to large buildings.
Because the system operates within the established
wavelength standards set for transmissions in the 1550-nanometer "window," it
offers a means of connecting end-users over dedicated wavelengths seamlessly across the
fiber and free-space transmission hops, officials said.
"The OpticAir system operates at 1550 nm, unlike
traditional over-the-air optical systems, which allows us to transmit in multiple
wavelengths and to use EDFAs," or erbium-doped fiber amplifiers, said Frank Galuppo,
director for OpticAir products in Lucent's optical-networking group.
For TV applications, Lucent is already talking with
television broadcasters about using the technology to backhaul studio-quality HDTV
signals, Galuppo said. "Broadcasters could set up our system at a live sports event
and transmit back to their studios, avoiding the need to set up high-capacity fiber
links," he added.
The system could also be used by broadcasters to distribute
their signals to cable headends, Galuppo noted. These types of applications require
transmissions in uncompressed format to ensure extremely high quality, and they cannot
easily be accommodated with traditional fiber feeds, Galuppo noted.
The OpticAir system is designed to meet the
high-performance requirements of traditional telecommunications markets, with reliability
at "four or five nines," or 99.99 to 99.999 percent, Galuppo said. Depending on
atmospheric conditions, this could mean distances limited to as little as 400 meters or as
far as 5 kilometers, although early versions of the system, to be deployed commercially
this spring, will be limited to 2 kilometers as a precautionary measure, he added.
"Fog is the worst problem by far, with snow and rain a
distant second," Galuppo said. Setting a 400-meter distance as the worst-case
parameter, the company believes atmosphere would not be a problem in most areas, even with
persistent fog patterns, he added.
The first OpticAir product will deliver one wavelength at
2.5 gigabits per second, with an eight-wavelength version due for production starting in
September. "We recently demonstrated 16 wavelengths, but we haven't set a time
frame for moving to that level," Galuppo said.
"I think it's safe to say that we have never had
market reception for a transmission product like we've seen for OpticAir," he
added. "The response has been more than overwhelming."
The product not only eliminates the cost of installing
fiber, but the actual transmission and receiving gear is slightly less expensive than such
gear would be for making the connection over fiber, Galuppo said.
This has important implications for the ability to get
reliable high-speed connections to large buildings, only 5 percent of which are connected
via fiber nationally, he said.
Another major application category for the technology is
the rapidly growing fixed-wireless industry, which needs some means of interconnecting
transmitter hubs.
Sprint Corp. is looking seriously at over-the-air optics as
an option for interconnecting the multiple MMDS (multichannel multipoint distribution
service) hubs it plans to install as it expands into two-way communications over the
wireless infrastructure, said Frank DeNap, director of the Advanced Technology Labs at
Sprint.
"It's one of the options we're considering
for our backhaul requirements, along with LMDS [local multipoint distribution service] and
fiber," DeNap said. "We could end up using all three, depending on local market
conditions."
For Sprint, the LMDS option would likely involve the use of
spectrum held by another provider, since it does not hold any LMDS spectrum. Meanwhile,
LMDS providers are likely users of the OpticAir system as they seek to maximize use of
their spectrum for reaching end-users while turning to other means to link their
transmitters.
"There's definitely a need to reserve our
spectrum if we can find a cheap alternative for backhaul," said a senior executive at
one of the leading LMDS license-holders, asking not to be named. "We're taking a
hard look at OpticAir, but it's too early to say whether it will meet our performance
requirements."
The OpticAir system uses what Galuppo called
"telescope" transmitters, four of which generate "expanded-beam"
signals to the targeted user premises in a way that minimizes dispersion of the light
through the air. The system meets the class-1 requirements of the safety standard for
optical transmissions, which means a person could look right into the transmitter with
binoculars and not be affected, he said.
The first publicly announced user of the OpticAir system is
long-haul carrier Global Crossing Ltd., which is launching field trials this month.
"If our testing of the product meets expectations, it
could offer a breakthrough method to help our global customers bypass local bottlenecks
and offer leading-edge services," Global Crossing senior vice president Wally Dawson
said.
