I almost forgot to add this interesting [and somewhat provocative] read on the subject, which can be found on this month's tele.com web site at:
teledotcom.com
"Startup promises optical breakthrough"
By Carl Weinschenk and Jason McKay
I've copied it below for posterity, since I belive it scrolls on the tele.com page at some point...
Looking for input here, folks, so jump in with any opinions, criticisms, questions or whatever comments you may have.
Enjoy, Frank C.
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November 6, 1998
"Startup promises optical breakthrough"
By Carl Weinschenk and Jason McKay
STARTUP SILKROAD INC. (San Diego) held a glitzy press conference near Wall Street in lower Manhattan this week to demonstrate what it calls a breakthrough technique for loading voice, data and video signals onto single-mode fiber.
The company made some extravagant claims. For instance, it said the technology -- called refractive synchronization communication -- is superior to dense wavelength-division multiplexing (DWDM), the technology network operators are increasingly using to satisfy exploding bandwidth demand.
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It has used the technology in its laboratories to send traffic at 200 Gbit/s and, the company said, the technology has the potential to operate at 10 Tbit/s.
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SilkRoad claimed at its Tuesday press conference that its technology, which it says is based on solutions to some of the most famous equations in physics, can potentially provide virtually unlimited two-way bandwidth. It has used the technology in its laboratories to send traffic at 200 Gbit/s and, the company said, the technology has the potential to operate at 10 Tbit/s. SilkRoad's first product is a bit more modest: a 30-channel one-way system, capable of speeds of up to 200 Gbit/s, available during the first quarter of 1999.
SilkRoad uses off-the-shelf externally modulated lasers. This type of laser impresses data into the signal path outside of the cavity where the light is produced. In the case of SilkRoad, the blocks of data -- each of which can represent a T1 (1.544 Mbit/s), a cable channel or anything else -- are separated by "flags," or tiny identifying tags that are outside the data being transported.
SilkRoad's main claim is that chairman and chief technical officer James Palmer has solved several esoteric physics equations collectively known as Maxwell's equations (after Scottish physicist James Maxwell, who posed them in the mid-19th century). They concern the relationship between space, time and bits of light, which are called photons. Up until now, scientists haven't solved these equations. Instead, they plug in assumptions that enable practical applications, such as optical networking. These assumptions are constraining, however, because they require use of separate frequencies (as in frequency-division multiplexing, or FDM) or time slots (as in time-division multiplexing, or TDM) for the transmission of data.
Palmer's answers enable massive increases in the amount of data transmitted by leaving ajar the doors between the three dimensions of space and the fourth of time, said Robert Freeman, SilkRoad's vice president of operations. Once the equations are plugged in, an important attribute of photons -- that they can act as if they have no mass -- can be exploited. Virtually any number of photons -- each signifying a tiny bit of information -- can perform the counterintuitive trick of occupying the same place at the same time without interfering with each other. The reason that they can travel in this ultimate car pool is that their lack of mass makes it impossible for them to influence or interfere with anything else. They are, in essence, like multiple overlapping shadows on a wall. At the detector -- the piece of gear that catches the laser light -- the reference signal is compared with the "flag" and the desired channel comes into focus, according to SilkRoad.
The other breakthrough SilkRoad claims is the solving of a different set of equations that deal with heat and how a photon reacts when it hits a surface. The narrower a frequency in which a signal is sent, the more sensitive it is to the energy present, which is manifest as heat. This heat distorts, or attenuates, the wavelength over a distance, eventually making it unusable. A system must therefore compensate for the heat produced. To date, however, heat compensation techniques are relatively unsophisticated and are only able to work on broader swaths of frequency. Palmer's work, Freeman said, enables scientists and technicians to develop supersensitive heat-compensation gear. This makes extremely narrow transmissions -- at 175 Hertz, almost 1,000 times narrower than today's 200-kHz standard -- possible. These narrow signals can travel farther before attenuating, SilkRoad said.
But the company's hefty claims raise many questions. Perhaps the most vital is whether the company's demonstrations and lab tests -- performed in controlled environments -- can be replicated in the real world. Opinions in the industry vary, and SilkRoad -- along with other new start-ups heralding new technologies -- must put their new equipment to the real-world test.
"In order to make evaluations on new technologies, what we really need to see is not only the first passed demonstration, but also get a real appreciation of what the trade-offs might be -- and every technology has them," said John Ryan, chief analyst with Ryan, Hankin, Kent Inc. (San Francisco).
SilkRoad could be in for a fight from competitors. "I'm hoping that these guys in fact can defend themselves and defend their patent in order to protect other people from leapfrogging them," said Robert Rosenberg, president, Insight Research Corp. (Parsippany, N.J.), market research firm. SilkRoad needs to have another trick up their sleeve, he said, in order to fend off larger companies with deeper pockets that might soon begin to breathe down their necks. "People will find ways in relatively short order to match what they're doing," he said.
Finally, there is the issue of whether the new technology, even if it proves out, can gain ground on DWDM. "It's hard to say that here comes the next technology when the other one is just beginning its life cycle," said Rosenberg. The international DWDM market in 1998 was $980 million and is expected to grow to $5.2 billion in 2003, according to Insight.
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