This article may be old info for this thread, but I just came across this article today. I posted on the SilkRoad thread, but not sure anyone goes there anymore.
I dug up this article on the web from Multichannel News (8-2-99). Any thoughts?
<New Products Could Be Big Leap for Fiber Optics
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Cable fiber-optic applications could take a quantum leap forward if either or both of two product-development strategies brought to light last week by two very. different suppliers live up to expectations.
In one approach to fostering a more flexible use of fiber, Scientific-Atlanta Inc. said it was investing $13 million in Bookham Technology Ltd. to promote development of a new generation of optoelectronic devices that could drive down the cost of extending fiber deeper into cable networks. Bookham has developed a means of forming complex optical circuits on mass-produced silicon chips. This has the potential to miniaturize and reduce the costs of products to be used in dense-wavelength-division multiplexing, return path transmissions and fiber-optic nodes.
The other development, involving the new optical transmission technology developed by startup SilkRoad Inc., is meant to greatly reduce the costs and increase the performance of fiber supertrunks used to transmit analog and digital signals among headends and primary distribution hubs.
SilkRoad, which recently conducted the first of several scheduled field tests of its technology in non-CATV applications, said its initial line of products slated for rollout in the first quarter of next year would include a system for cable that will bidirectionally transmit multiple feeds of analog and digital TV as well as telecommunications signals. This would occur in their native formats, on a single wavelength at distances well beyond the unamplified transmission capabilities of today's AM (amplitude-modulated)supertrunks.
The most immediate impact from the developments at these firms could come from S-A,which is already testing some Bookham products in hopes of quickly converting them for
use in cable. "If these pan out, we could have products available within six to eight months," said Paul Connolly, vice president of marketing and network architectures at S-A.
"In instances where we have to design from the ground up for our applications, we're probably looking at a 12- to 18-month timeframe," he added.
Bookham's patented technique involves the alignment of passive optical components onto silicon chips while using standard silicon-chip production techniques to produce many
devices at low costs. The resulting miniaturization of the complex circuitry involved in the interface between electronic devices and optical receivers, waveguides and other components plays well with the needs of architectures such as the "Lightwire" system AT&T Broadband & Internet Services is preparing to test in San Diego, Connolly noted.
"What you end up with is the equivalent of ASICs (application-specific integrated circuits) in electronics, where you can take standard cells and cut devices in mass
quantities to meet specific industry needs," Connolly said. "We believe they're unique in the world in being able to do this on silicon."
Bookham, based in Oxford, England, has already taken on Intel Corp. and Cisco Systems Inc. as equity partners for development of components in the computing and routing sectors. S-A, as the third industry-specific equity partner, will help guide the development of ASOPs for cable, Connolly said, declining to discuss other terms of the agreement.
One of the applications S-A is exploring with Bookham would be able to integrate a wavelength demultiplexer and photoreceiver onto the chip, thereby creating a
miniaturized, low-cost means of handing off a wavelength from a multiwavelength stream at a micronode on the coaxial plant. This way a single fiber could serve multiple
micronodes with dedicated wavelengths, vastly lowering the cost of extending fiber deep into the cable plant, as AT&T is doing in its Lightwire trial.
S-A said it had also reached an agreement to acquire the photonic business units of U.K.-based Thomas & Betts, which has been supplying components used in S-A's four-port node return path system. The good density characteristics of these components allow return signals to be multiplexed digitally from different coax return feeds for return
transmission over a single fiber.
At SilkRoad, the technical breakthrough has to do with the ability to deliver very high volumes of traffic over a single wavelength, which could prove to be a cheaper option for maximizing fiber capacity than DWDM, if the company's claims prove out.
While SilkRoad eventually expects to offer gear that would facilitate fiber applications in any part of any network, its initial CATV product is focused on supertrunking, starting with an optical transceiver (transmitter/receiver) product line to be made available commercially in the first quarter of next year that will support delivery of four, eight or 16 separate bands of information on the same wavelength. The company said each band can deliver up to 1.5 gigahertz of RF TV signals or digital electrical spectrum of up to 650 MHz or a Sonet OC3 (155 megabits per second) or OC-12 (620 mbps) signal, with any combination of band configurations in either direction.
If the system is used to carry analog TV signals, it can transmit up to 100 MHz without amplification or about twice the distance of standard AM fiber systems, officials said.
Transmission distances are longer in all-digital mode.
The immediate push in the cable TV product-development effort comes from a regional Bell company that wants to be able to combine its analog TV channels with delivery of
OC12 and OC-48 (2.5 gigabits per second) signals over a single fiber, said SilkRoad president and CEO Kevin Doria. "They asked us to build and design a network for them, and we'll be testing this in the next few months," he said.
Doria said the company will also introduce a commercial product line for the enterprise market in the first quarter, with various versions supporting anywhere from four to 16
mixed-technology payloads consisting of OC-3 or -12 or digital video in each path or, alternatively, fewer paths of OC-48 payloads, ranging from one to four.
The company conducted a trial of the technology July 23 with an unnamed oil and gas company at San Diego State University. It delivered a computer-to-computer OC-12
pay* load over a distance of 80 kilometers directly from and to OC-12 cards installed in Silicon Graphics computers, without use of intervening multiplexing or switching equipment, Doria said.
"Our next test will be over a Qwest (Communications) link between Los Angeles and San Diego," Doria added. This test, also operating at OC-12 rates, will cover a distance
of 200 kilometers, for delivery of a 300 gigabyte file, he said.
The commercial digital communications products will be designed to propagate a distance of 500 kilometers without amplification, Doria noted. While the capacity levels
envisioned for these initial products don't approach the limits of DWDM systems on the commercial market, the SilkRoad systems will achieve what DWDM systems do at much
lower cost. This is because they only require use of a single laser and a high-frequency external modulation system, officials said.
Moreover, they added, the technology eventually will support products that approach the physical capacity limits of fiber, at somewhere around 10 terabits per second, which is
currently well beyond the reach of DWDM.
While many observers have been skeptical of SilkRoad's ability to make its physical principles work in real-world field applications, Doria and his colleagues asserted the test last week and others planned over the months ahead clearly show that the technology is practical. The company has a licensing and development agreement with NASA under
which the two entities are creating high-frequency detectors now operating at 300 GHz and soon to move to 500 GHz and later to 1.5 teraHertz, they noted.
High-frequency modulation and demodulation components are one key to the way SilkRoad's technology works. Another essential element in what the company calls "refractive synchronization communication' is the use of multiple properties of photons to carry information.
SilkRoad's system is being tested by a number of long-distance and competitive local-exchange carriers, said Dataquest analyst Ken Kelly, who recently completed a
report on the SilkRoad technology. One company, Level 3 Communications, was willing to have its name used in the report, with unnamed officials telling Kelly that while they
have some reservations, they expect to use the technology once it becomes commercially available.
"In fact," Kelly reported, "an executive at Level 3 believes all or most carriers will eventually deploy it."
A Level 3 spokesman refused to comment on the company's position. "We don't discuss vendors, even the ones we're contracted with, let alone any we're conducting tests with,"
he said.
As for the CATV application of SilkRoad's technology, Kelly said, "I saw the system demonstrated with TV signals, and it lives up to its claims."
SilkRoad officials said they had not set pricing for the new CATV supertrunking system, but indicated it would match the costs of AM systems and be significantly cheaper than digital options.> |
