Dark Fibre, Dumb Network George Gilder / MCI ID: 409-1174 The following article, INTO THE
Dark Fibre, Dumb Network
George Gilder / MCI ID: 409-1174
The following article, INTO THE FIBERSPHERE, was first published
in slightly different and shorter form in Forbes ASAP, December 7,
1993. It is a portion of my book, Telecosm, which will be published
next year by Simon & Schuster, as a sequel to Microcosm, published in
1989 and Life After Television published by Norton in 1992.
Subsequent chapters of Telecosm will be serialized in Forbes ASAP
beginning with the March issue containing a theory of wireless
PLEASE POST FIBERSPHERE TO ANY USENET
NEWSGROUPS THAT MAY BE DEEMED SUITABLE.
THE COMING OF THE FIBERSPHERE
In a world of dumb terminals and telephones,
networks had to be smart. But in a world of
smart terminals, networks have to be dumb.
Philip Hope, divisional vice president for engineering systems
of EDS, has an IQ problem. His chief client and owner, General
Motors, wants to interconnect thousands of 3-D graphics and computer
aided engineering (CAE) workstations with mainframes and
supercomputers at Headquarters, with automated assembly equipment at
factories in Lordstown, Indiana, and Detroit, with other powerful
processors at their technical center in Warren, Michigan, with their
Opel plant in Ruesselheim, Germany, and with their design center
outside San Diego. On behalf of another client, Hope wants to link
multimedia stations for remote diagnostics, X-ray analysis, and
pharmaceutical modeling in hospitals and universities across the
Any function involving 3-D graphics, CAE, supercomputer
visualization, lossless diagnostic imaging, and advanced medical
simulations demands large bandwidth or communications power.
Graphics workstations often operate screens with a million picture
elements (pixels), and use progressive scanning at 60 frames or
images a second. Each pixel may entail 24 bits of color. That adds
up fast to billions of bits (gigabits) a second. And that's for last
year's technology in a computer industry that is doubling its powers
and cost effectiveness every year.
What Hope needs is bandwidth and connections. The leading
bandwidth and connections people have always been the telephone
companies. But when Hope goes to the telephone companies, they want
to tell him about intelligence: their Advanced Intelligent Network
which will be coming on line over the next decade or so and will
solve all his problems. For now, they have what they call DS-3
services available in many areas, operating T-3 lines at 45 megabits
(million bits) a second. These facilities are ample for most
computer uses and working together with several different Regional
Bell Operating Companies (RBOCs), Hope should be able to acquire
these services in time for a General Motors takeover by Toyota.
Hope has been through this before. In the early 1980s, he
actually wanted D-3 services. Then he was interconnecting facilities
in Southeast, Michigan, with plants in Indiana and Ohio. But
Michigan Bell could not supply the lines in time. EDS had to build a
network of microwave towers to bear the 45 megabit traffic. Later in
the decade, the phone companies have even offered him higher capacity
fiber optic lines, with the requirement that the optical bits be
slowed down and run periodically through an electronic interface so
the telco could count the number of equivalent channels being used.
What Hope and others in the systems integration business need is
not intelligent networks tomorrow but dumb bandwidth that they can
deliver to their customers flexibly, cheaply, and now. To prepare
for future demand, they want the network to use fiber optics. It so
happens that America's telephone companies have some two million
miles of mostly unused fiber lines in the ground today, kept as
redundant capacity for future needs. Hope would like to be able to
tap into this dark fiber for his own customers.
As a leader in the rapidly expanding field of computer services,
EDS epitomizes the needs of an information economy. With a backlog
of 22 billion dollars in already contracted business, EDS is
currently a seven billion dollar company growing revenues at an
annual rate of 15 percent, some three times as fast as the phone
companies. EDS will add a billion dollars or so in new sales in 1992
alone. If the company is to continue to supply leading edge services
to its customers, it must command leading edge communications. To
EDS, that means dumb and dark networks.
THE DARK FIBER CASE
That need has driven EDS into an active role as an ex parte
pleader in Federal Case 911416, currently bogging down in the
District of Columbia Federal Court of Appeals as the so-called dark
fiber case. On the surface, the case, known as Southwestern Bell et
al versus the Federal Communications Commission and the U.S. Justice
Department, pits four Regional Bell telephone companies against the
FCC. But the legal maneuvers actually reflect a rising conflict
between the Bells and several large corporate clients over the future
Beyond all the legal posturing, the question at issue is whether
fiber networks should be dumb and dark, and cheap, the way EDS and
other customers like them. Or whether they should be bright and
smart, and strategically priced, the way the telephone companies want
On the side of intelligence and light are the phone companies;
Southwestern Bell, U.S. West, Bell South, and Bell Atlantic. The
forces of darkness include key officials at the FCC and such
companies as Shell Oil, the information services arm of McDonald
Douglas, long distance network provider Wiltel, as well as EDS.
For most of the four year course of the struggle, it has passed
unnoticed by the media. In summary, the issue may not seem
portentous. The large corporate customers want dark fiber; the FCC
mandates that it be supplied; the Bells want out of the business.
But for all their obscurity, the proceedings raise what for the next
twenty years will be the central issue in communications law and
technology. The issue, if not the possible trial itself, will shape
the future of both the computer and telephone industries during a
period when they are merging to form the spearhead of a new
Dark fiber is simply a glass fiber optic thread with nothing
attached to it, (ie. no light being sent through it). In this unlit
condition, it is available for use without the intermediation of
phone company electronics or intelligent services.
In the mid-1980s, the Bells leased some of their dark fiber
lines to several large corporations on an individual case basis.
These companies learned to love dark fiber. But when they tried to
renew their leases with the Bells, the Bells clanged no! Why don't
you leave the interconnections and protocols to us? Why don't you
use our marvellous smart network with all the acronyms and
intelligent services? Why don't you let us meter your use of the
fiber and send you a convenient monthly bill for each packet of bits
EDS and the other firms rejected the offer; they preferred that
dumb fiber to the intelligent network. When the Bells persisted in
an effort to deny new leases, the companies went to the FCC to
require the Bells, as regulated common carrier telephone companies,
to continue supplying dark fiber.
In the fall of 1990, the FCC ruled that the phone companies
would have to offer dark fiber to all comers under the rules of
common carriage. Rather than accept this new burden, the phone
companies petitioned to withdraw from the business entirely under
what is called a rule 214 application. Since the FCC has not acted
on this petition, the Bells are preparing to go to court to force the
issue. Their corporate customers are ready to litigate as well.
It is safe to say that none of the participants fully comprehend
the significance of their courthouse confrontation. To the Bells,
after all is said and done, the key problem is probably the price.
Under the existing tariff, they are required to offer this service to
anyone who wants it for an average price of approximately $150 per
strand of fiber per month. As an offering that competes with their
T-3 45 megabit (millions of bits) a second lines and other
forthcoming marvels, dark fiber threatens to gobble up their future
as vendors of broadband communications to offices, even as cable TV
preempts them as broadband providers to homes. Since the Bells'
profits on data are growing some 10 times as fast as their profits on
voice telephony, they see dark fiber as a menace to their most
The technological portents, however, are far more significant
even than the legal and business issues. The coming triumph of dark
fiber will mean not only the end of the telephone industry as we know
it but also the end of the telephone industry as they plan it: a vast
intelligent fabric of sophisticated information services. It also
could mean a thoroughgoing restructuring of a computer industry
increasingly dedicated to supplying smart networks. Indeed, for most
of the world's communications companies, professors of communications
theory, and designers of new computer networks, the triumph of dark
and dumb means back to the drawing board, if not back to the dark
But the new dark ages cannot be held back.
Springing out the depths of IBM's huge Watson Laboratories is a
powerful new invention: the all optical network, that will soon
relegate all bright and smart executives to the Troglodyte file and
make dumb and dark the winning rule in communications.
THE WRINGER EFFECT
From time to time, the structure of nations and economies goes
through a technological wringer. A new invention radically reduces
the price of a key factor of production and precipitates an
industrial revolution. Before long, every competitive business in
the economy must wring out the residue of the old costs and customs
from all its products and practices.
The steam engine, for example, drastically reduced the price of
physical force. Power once wreaked at great expense from human and
animal muscle pulsed cheaply and tirelessly from machines burning
coal and oil. Throughout the world, dominance inexorably shifted to
businesses and nations that reorganized themselves to exploit the
suddenly cheap resource. Eventually every human industry and
activity, from agriculture and sea transport to printing and war, had
to centralize and capitalize itself to take advantage of the new
Putting the world through the technological wringer over the
last three decades has been the integrated circuit, the IC. Invented
by Robert Noyce of Intel and Jack Kilby of Texas Instruments in 1959,
the IC put entire systems of tiny transistor switches, capacitors,
resistors, diodes, and other once costly electronic devices on one
tiny microchip. Made chiefly of silicon, aluminum, and oxygen, three
of the most common substances on earth, the microchip eventually
reduced the price of electronic circuitry by a factor of a million.
As industry guru Andrew Rappaport has pointed out, electronic
designers now treat transistors as virtually free. Indeed, on memory
chips, they cost some 400 millionths of a cent. To waste time or
battery power or radio frequencies may be culpable acts, but to waste
transistors is the essence of thrift. Today you use millions of them
slightly to enhance your TV picture or to play a game of solitaire or
to fax Doonsbury to Grandma. If you do not use transistors in your
cars, your offices, your telephone systems, your design centers, your
factories, your farm gear, or your missiles, you go out of business.
If you don't waste transistors, your cost structure will cripple you.
Your product will be either too expensive, too slow, too late, or too
low in quality.
Endowing every information age engineer or PC hacker with the
creative potential of a factory owner of the industrial age, the
microchip reversed the centralizing thrust of the previous era. All
nations and businesses had to adapt to the centrifugal law of the
microcosm, flattening hierarchies, outsourcing services, liberating
engineers, shedding middle management. If you did not adapt your
business systems to the new regime, you would no longer be a factor
in the world balance of economic and military power.
During the next decade or so, industry will go through a new
technology wringer and submit to a new law: the law of the telecosm.
The new wringer, the new integrated circuit, is called the all
optical network. It is a communications system that runs entirely in
glass. Unlike existing fiber optic networks, which convert light
signals to electronic form in order to amplify or switch them, the
all optical network is entirely photonic. From the first conversion
of the signal from your phone or computer to the final conversion to
voice or data at the destination, your message flies through glass on
wings of light.
Just as the old integrated circuit put entire electronic systems
on single slivers of silicon, the new IC will put entire
communications systems on seamless webs of silica. Wrought in
threads as thin as a human hair, this silica is so pure that you
could see through a window of it seventy miles thick. But what makes
the new wringer roll with all the force of the microchip revolution
before it is not the purity but the price. Just as the old IC made
transistor power virtually free, the new IC, the all optical network,
will make communications power virtually free.
Another word for communications power is bandwidth. Just as the
entire world had to learn to waste transistors, the entire world will
now have to learn how to waste bandwidth. In the 1990s and beyond,
every industry and economy will go through the wringer again.
The impact on the organization of companies and economies,
however, has yet to become clear. What is the law of the telecosm?
Will the new technology reverse the centrifugal force of the
microchip revolution...or consummate it? To understand the message
of the new regime, we must follow the rule of microcosmic prophet
Carver Mead of Caltech: Listen to the technology...and find out what
it is telling us.
THE SHANNON-SHOCKLEY REGIME
The father of the all-optical-network, the man who coined the
phrase, built the first fully functional system, and wrote the
definitive book on the subject, is Paul E. Green, Jr. of Watson
Laboratory at IBM. Now standing directly in the path of Green's
wringer is Robert Lucky, who some seven years ago at a conference at
Cornell first gave Green the idea that an all optical network might
The leading intellectual in telephony, Lucky recently shocked
the industry by shifting from ATC Bell Labs, where he was executive
director of research, to Bellcore, the laboratory of the Regional
Bell Operating Companies (RBOCs). There he will soon have to
confront the implications of Green's innovation.
Contemplating the new technology, Lucky recalls a course on data
networks that he used to teach many years ago with Green. As a
computer man, Green relished the contrast between the onrushing
efficiencies in his technology and the relative dormancy in
communications. Indeed, for some twenty five years, while computer
powers rose a millionfold, network capacities increased about a
thousandfold. It was not until the late 1980s that most long
distance data networks much surpassed the Pentagon's ARPANET running
at 50 kilobits (thousands of bits) per second since the mid sixties.
This was the era dominated by the powerful mathematic visions
and theories of Claude Shannon of MIT and Bell Labs. Shannon was the
reclusive genius who invented Information Theory to ascertain the
absolute carrying capacity of any communications channel.
Whether wire or air, channels were assumed to be narrow and
noisy, the way God made them (sometimes with help from AT&T).
Typical were the copper phone lines that still link every household
to the telephone network and the air waves that still bear radio and
television signals and static.
The all-purpose remedy for these narrow, noisy channels was
powerful electronics. Invented at Bell Laboratories by a team headed
by William Shockley and then developed by Robert Noyce and other
Shockley proteges in Silicon Valley, silicon transistors and
integrated circuits engendered a constant exponential upsurge of
Throwing ever more millions of ever faster and cheaper
transistors at every problem, engineers created fast computers,
multiplexors, and switches that seemed to surmount and outsmart every
limit of bandwidth or restriction of wire. This process continues
today with heroic new compression tools that allow the creation of
full video conferences over 64 kilobit telephone connections.
Scientists at Bellcore are now even proposing new ways of using the
Motion Picture Engineering Group (MPEG) compression standard to send
full motion movies at 1.5 megabits a second over the 4 kilohertz
twisted pair copper wires to the home. Using ever faster computers,
the telephone company is saying it can give you pay-per- view movies
without installing fiber, or even coaxial cable, to the home.
In the Shannon-Shockley era, the communications might be noisy
and error prone, but smart electronics could encode and decode
messages in complex ways that allowed efficient identification and
correction of all errors. The Shannon channel might be narrow, but
fast multiplexors allowed it to be divided into time slots
accommodating a large number of simultaneous users in a system called
time division multiplexing. The channel might clog up when large
numbers of users attempted to communicate with each other at once,
but collision detectors or token passers could sort it all out in
nanoseconds. Graphics and video might impose immense floods of bits
on the system, but compression technology could reduce the floods to
a manageable trickle with little or no loss of picture quality.
If all else failed, powerful electronic switches could
compensate for almost any bandwidth limitations. Switching could
make up for the inadequate bandwidth at the terminals by relieving
the network of the need to broadcast all signals to every
destination. Instead, the central switch could receive all signals
and then route them to their appropriate addresses.
To this day, this is the essential strategy of the telephone
companies: compensate for narrow noisy bandwidth with ever more
powerful and intelligent digital electronics. Their core competence,
the Bells hasten to tell you, is switching. They make up for the
shortcomings of copper wires by providing smart, powerful digital
Their vision for the future is to join the computer business all
the way, making these switches the entering wedge for ever more
elaborate information services. Switches will grow smarter and more
sophisticated until they provide an ever growing cornucopia of
intelligent voice and fax features, from caller ID and voice mail to
personal communications systems that follow you and your number
around the world from your car commute to your vacation beach
hideaway. In the end, these intelligent networks could supply
virtually all the world's information needs, from movies, games and
traffic updates to data libraries, financial services, news programs,
and weather reports, all climaxing with yellow pages that exfoliate
into a gigantic global mall of full motion video where your fingers
walk (or your voice commands echo) from Harrods, to Jardines, to
Akihabara, to Century 21 without you leaving the couch.
At the time when Green and Lucky taught their course, this
strategy for the future was only a glimmer in the minds of telephone
But the essence of it was already in place. As Green pointed out,
telephone companies' response to sluggishness in communications was
to enter the computer industry, where progress was faster. The
creativity of digital electronics would save the telephone industry
from technical stagnation.
Lucky, however, protested to Green that it was unjust to compare
the two fields. Computers and telecom, as Lucky explained it,
operate on entirely different scales. Computers work in the
microscale world of the IC, putting ever more thousands of wires and
switches on single slivers of silicon.
By contrast, telecommunications functions in the macroworld,
laying out wires and switches across mostly silicon landscapes and
seabeds. It necessarily entails a continental, or even
intercontinental stretch of cables, microwave towers, switches, and
poles. How was it possible, Lucky asked, to make such a large scale
system inexpensive? Inherent in the structure and even the physics
of computers and telecommunications, so it seemed to Lucky two
decades ago, was a communications bottleneck.
As Lucky remembers it, Green was never satisfied with Lucky's
point. Green believed that someday communications could achieve
miracles comparable to the integrated circuit in computing....
THE BANDWIDTH SCANDAL
Today, as Lucky was the first to announce, fiber optics has
utterly overthrown the previous relationship between fast computers
and slow wires. Now it is computer technology that imposes the
bottleneck on the vast vistas of dark fiber.
A silicon transistor can change its state some 2.5 billion times
a second in response to light pulses (bundles of photons) hitting a
photo- detector. Since it would take a human being a thousand years
or so of 10 hour workdays even to count to two billion, two billion
cycles in a single second (two gigahertz) might seem a sprightly
pace. But in the world of fiber optics running at the speed and
frequencies of light, even a rate of two billion cycles a second is a
humbling bow to the slothful pace of electronics. Since optical
signals still have to be routed to their destinations through
computer switches, communications now suffers from what is known as
the electronic bottleneck.
It is this electronic bottleneck, the entire Bell edifice of
Shannon and Shockley, that Paul Green plans to blow away with his all
optical networks. Green is targeting what is a secret scandal of
modern telecommunications: the huge gap between the real capacity of
fiber optics and the actual speed of telephone communications.
In communications systems, the number of waves per second (or
hertz) represents a rough measure of its potential bandwidth or
ultimate carrying capacity. The bandwidth of a radio system, for
example, is determined by the frequency of each station or channel
and by the number of stations that can fit within the band. Your AM
dial, for example, runs from around 535 thousand hertz (kilohertz) to
1705 kilohertz and each station uses some 10 kilohertz. With an
ideal receiver, the AM passband might carry 117 stations.
By contrast, the intrinsic bandwidth of one strand of dark fiber
is some 25 thousand gigahertz in each of three groups of frequencies
(three passbands) through which fiber can transmit light over long
distances. At a gigahertz per terminal, this bandwidth might
accommodate some 25,000 supercomputer stations (or 2.5 billion AM
stations). Using what is called dispersion shifted fiber, it may be
possible to use two of these passbands at once: a total of some 40 or
50 thousand gigahertz. For comparison, consider all the radio
frequencies currently used in the air for radio, television,
microwave, and satellite communications and multiply by two thousand.
The bandwidth of one fiber thread could carry more than two thousand
times as much information as all these radio and microwave
frequencies that currently comprise the air. One fiber thread could
bear twice the traffic on the phone network during the peak hour of
Mothers' Day in the U.S. (the heaviest load currently managed by the
Yet even for point-to-point long distance links, let alone
connections to homes, telephone and computer network engineers now
turn their backs on this immense capacity and use perhaps one or two
fifty thousandths it. Deferring to the electronic bottleneck, the
telephone industry uses fiber merely as a superior replacement for
the copper wires, coaxial cables, satellite links, and microwave
towers that connected the local central office switches to one
another for long distance calls.
Over the last 15 years, the Bell Laboratory record for fiber
optics communication has run from 10 megabits per second over a one
kilometer span to some 10 gigabits per second over nearly one
thousand kilometers. But all the heroic advances in point-to-point
links between central offices continued to use essentially one
frequency on a fiber thread, while ignoring its intrinsic power to
accommodate thousands of useful frequencies.
In a world of all optical networks, this strategy is bankrupt.
No longer will it be possible to throw more transistors, however
cheap and fast, at the switching problem. Electronic speeds have
become an insuperable bottleneck obstructing the vast vistas of dark
So called gigabit networks planned by the telephone and computer
companies will not do. What is needed is not a gigabit spread among
many terminals, but a large network functioning at a gigabit per
second per terminal.
The demands of EDS offer a hint of the most urgent business
needs. Added to them will be consumer demands. True high definition
television, comparable to movies in resolution, requires close to
gigabit-a-second bandwidth, particularly if the program is dispatched
to the viewer in burst mode all at once in a few seconds down the
fiber, or if the user is given a chance to shape the picture, choose
a vantage point, window several images at once, or experience three
dimensions. When true broadband channels become available, there
will be a flood of new applications comparable to the thousands of
new uses of the IC.
No foreseeable progress in electronics can overcome the
electronic bottleneck. To do that, we need an entirely new
communications regime. In the form of the all optical network, this
regime is now at hand.
LAW OF THE TELECOSM: NETWORKS DUMB AS A STONE
The new regime will use fiber not as a replacement for copper
wires but as a new form of far more capacious and error-free air.
Through a system called wavelength division multiplexing and access,
computers and telephones will tune into desired messages in the
fibersphere the same way radios now tune into desired signals in the
atmosphere. The fibersphere will be intrinsically as dumb and dark
as the atmosphere.
The new regime overcomes the electronic bottleneck by altogether
banishing electronics from the network. But, ask the telcos in
unison, what about the switches? As long as the network is switched,
it must be partly electronic. Unless the network is switched, it is
not a true any- to-any network. It is a broadcast system. It may
offer a cornucopia of services. But it cannot serve as a common
carrier like the phone network allowing any party to reach any other.
Without intelligent switching it cannot provide personal
communications nets that can follow you wherever you go. Without
intelligent switching, the all optical network, so they say, is just
a glorified cable system.
These critics fail to grasp a central rule of the telecosm:
bandwidth is a nearly perfect substitute for switching. With
sufficient physical bandwidth, it is possible to simulate any kind of
logical switch whatsoever. Bandwidth allows creation of virtual
switches that to the user seem to function exactly the way physical
switches do. You can send all messages everywhere in the network,
include all needed codes and instructions for correcting, decrypting,
and reading them, and allow each terminal to tune into its own
messages on its own wavelength, just like a two-way radio. When the
terminals are smart enough and the bandwidth great enough, your all
optical network can be as dumb as a stone.
Over the last several years, all optical network experiments
have been conducted around the world, from Bellcore in New Jersey to
NTT at Yokosuka, Japan. British Telecom has used wavelength division
multiplexing to link four telephone central offices in London.
Columbia's Telecom Center has launched a Teranet that lacks tunable
lasers or receivers but can logically simulate them. Bell
Laboratories has generated most of the technology but as a long
distance specialist has focussed on the project of sending gigabits
of information thousands of miles without amplifiers. But only fully
functional system is the Rainbow created by Paul Green at IBM.
As happens so often in this a world of technical disciplines
sliced into arbitrary fortes and fields, the large advances come from
the integrators. Paul Green is neither a laser physicist, nor an
optical engineer, nor a telecommunications theorist. At IBM, his
work has ranged from overseeing speech recognition projects at Watson
Labs to shaping company strategy at corporate headquarters in Armonk.
His most recent success was supervising development of the new APPN
(Advanced Peer to Peer Network) protocol. According to an IBM
announcement in March, APPN will replace the venerable SNA (systems
network architecture) that has been synonymous with IBM networking
for more than a decade.
Green took some pride in this announcement, but by that time,
the project was long in his past. He was finishing the copy editing
on his magisterial tome on Fiber Optic Networks (published this
summer by Prentice Hall). And he was moving on to more advanced
versions of the Rainbow which he and his team had introduced in
December 1991 at the Telecom 91 Conference in Geneva and which has
been installed between the various branches of Watson Laboratories in
Westchester County, N.Y.
As Peter Drucker points out, a new technology cannot displace an
old one unless it is proven at least 10 times better. Otherwise the
billions of dollars worth of installed base and thousands of
engineers committed to improving the old technology will suffice to
block the new one. The job of Paul Green's 15 man team at IBM is to
meet that tenfold test.
Green's all optical network creates a fibersphere as neutral and
passive as the atmosphere. It can be addressed by computers the same
way radios and television sets connect to the air. Consisting
entirely of unpowered glass and passive spitters and couplers, the
fibersphere is dark and dumb. Any variety of terminals can
interconnect across it at the same time using any protocols they
Just as radios in the atmosphere, computer receivers connected
to the fibersphere do not find a series of bits in a message; they
tune into a wavelength or frequency. Because available Fabry Perot
tunable filters today have larger bandwidth than tunable lasers,
Green chose to locate Rainbow's tuning at the receiver and have
transmitters each operate at a fixed wavelength. But future networks
can use any combination of tunable equipment at either end.
When Green began the project in 1987, the industry stood in the
same general position as the pioneers of radio in the early years of
that industry. They had seemingly unlimited bandwidth before them,
but lacked transmitters and receivers powerful enough to use it
effectively. Radio transmitters suffered splitting losses as they
broadcast their signals across the countryside. Green's optical
messages lose power everytime they are split off to be sent to
another terminal or are tapped by a receiver.
The radio industry solved this problem by the development of the
audion triode amplifier. Green needed an all optical amplifier to
replace the optoelectronic repeaters that now constitute the most
widespread electronic bottleneck in fiber. Amplifiers in current
fiber networks first convert the optical signal to an electronic
signal, enhance it, and then convert it back to photons.
Like the pioneers of radio, Green soon had his amplifier in
hand. Following concepts pioneered by David Payne at the University
of Southhampton in England, a Bell Laboratories group led by Emmanuel
Desurvire and Randy Giles developed a workable all optical device.
They showed that a short stretch of fiber doped with erbium, a rare
earth mineral, and excited by a cheap laser diode, can function as a
powerful amplifier over the entire wavelength range of a 25,000
gigahertz system. Today such photonic amplifiers enhance signals in a
working system of links between Naples and Pomezia on the west coast
of Italy. Manufactured in packages between two and three cubic
inches in size, these amplifiers fit anywhere in an optical network
for enhancing signals without electronics.
This invention overcame the most fundamental disadvantage of
optical networks compared to electronic networks. You can tap into
an electronic network as often as desired without weakening the
voltage signal. Although resistance and capacitance will weaken the
current, there are no splitting losses in a voltage divider.
Photonic signals, by contrast, suffer splitting losses every time
they are tapped; they lose photons until eventually there are none
left. The cheap and compact all optical amplifier solves this
Not only did Green and his IBM colleagues create working all
optical networks, they also reduced the interface optoelectronics to
a single microchannel plug-in card that can fit in any IBM PS/2 level
personal computer or R6000 workstation. Using off-the-shelf
components costing a total of $16,000 per station, Rainbow achieved a
capacity more than 90 times greater than FDDI at an initial cost
merely four times as much.
Just as Jack Kilby's first ICs were not better than previous
adders and oscillators, the Rainbow I is not better in some respects
than rival networks based on electronics. At present it connects
only 32 computers at a speed of some 300 megabits per second, for a
total bandwidth of 9.5 gigabits. This rate is huge compared to most
other networks, but it is still well below the target of a system
that provides gigabit rates for every terminal.
A more serious limitation is the lack of packet switching.
Rather than communicating down a dedicated connection between two
parties, like phones do, computer networks send data in small
batches, called packets, each bearing its own address. This requires
switching back and forth between packets millions of times a second.
Neither the current Rainbow's lasers nor its filters can tune from
one message to another more than thousands of times a second. This
limitation is a serious problem for links to mainframes and
supercomputers that may do many tasks at once in different windows on
the screen and with connections to several other machines.
As Green shows, however, all these problems are well on the way
to solution. A tide of new interest in all optical systems is
sweeping through the world's optical laboratories. The Pentagon's
Defense Advanced Projects Agency (DARPA) has launched a program for
all optical networking. With Green installed as the new President of
the IEEE Communications Society, the technical journals are full of
articles on new wavelength division technology. Every few months
brings new reports of a faster laser with a broader bandwidth, or
filter with faster tuning, or an ingenious new way to use bandwidth
to simulate packet switching. Today lasers and receivers can switch
fast enough but they still lack the ability to cover the entire
The key point, however, is that as demonstrated both in Geneva
and Armonk, the Green system showed the potential efficiency of all
optical systems. Even in their initial forms they are more cost
effective in bandwidth per dollar than any other network technology.
Scheduled for introduction within the next two years, Rainbow III
will comprise a thousand stations operating at a gigabit a second,
with the increasingly likely hope of fast packet switching
capability. At that point, the system will be a compelling
commercial product at least hundreds of times more cost effective
than the competition.
Without access to dark fiber, however, these networks will be
worthless. If the telephone companies fail to supply it, they risk
losing most of the fastest growing parts of their business: the data
traffic which already contributes some 50 percent of their profits.
But there is also a possibility that they will lose much of their
potential consumer business as well: the planned profits in
pay-per-view films and electronic yellow pages. This is the message
of a second great prophet of dark fiber, Will Hicks of Southbridge,
A venerable inventor of scores of optical products, Hicks
believes that Green's view of the future of fiber is too limited.
Using wavelength division, Hicks can see the way to deliver some 500
megahertz two-way connections to all the homes in America for some
$400 per home. That is fifty times the 10 megahertz total capacity
of an Ethernet (with no one else using it) for some 20 percent of the
cost. That is capacity in each home for twenty digital two-way HDTV
channels at once at perhaps half the cost of new telephone
connections. Then, after a large consumer market emerges for fiber
optics, Hicks believes, Green's sophisticated computer services will
follow as a matter of course.
The consumer market, Hicks maintains, is the key to lowering the
cost of the components to a level where they can be widely used in
office networks as well. He cites the example of the compact disk
laser diode. Once lasers were large and complex devices, chilled with
liquid nitrogen, and costing thousands of dollars; now they are as
small as a grain of salt, cheap as a box of cereal, and more numerous
than phonograph needles. An executive at Hitachi told Hicks that
Hitachi could work a similar transformation on laser diodes and
amplifiers for all optical networks. Just tell me what price you want
to pay and I'll tell you how many you have to buy.
The divergence of views between the IBM executive and the
wildcat inventor, however, is far less significant than their common
vision of dark fiber as the future of communications. By the power
of ever cheaper bandwidth, it will transform all industries of the
coming information age just as radically as the power of cheaper
transistors transformed the industries of the computer age.
For the telephone companies, the age of ever smarter terminals
mandates the emergence of ever dumber networks. This is a major
strategic challenge; it takes a smart man to build a dumb network.
But the telcos have the best laboratories and have already developed
nearly all the components of the fibersphere.
Telephone companies may complain of the large costs of the
transformation of their system, but they command capital budgets as
large as the total revenues of the cable industry. Telcos may recoil
in horror at the idea of dark fiber, but they command webs of the
stuff ten times larger than any other industry. Dumb and dark
networks may not fit the phone company self-image or advertising
posture. But they promise larger markets than the current phone
company plan to choke off their future in the labyrinthine nets of an
intelligent switching fabric always behind schedule and full of
The telephone companies cannot expect to impose a uniform
network governed by universal protocols. The proliferation of
digital protocols and interfaces is an inevitable effect of the
promethean creativity of the computer industry. Green explains, You
cannot fix the protocol zoo. You must use bandwidth to accommodate
As Robert Pokress, a former switch designer at Bell Labs now
head of Unifi Corporation, points out, telephone switches (now 80
percent software) are already too complex to keep pace with the
efflorescence of relatively simple computer technology on their
periphery. While computers become ever more lean and mean, turning
to reduced instruction set processors, networks need to adopt reduced
instruction set architectures. The ultimate in dumb and dark is the
fibersphere now incubating in their magnificent laboratories.
The entrepreneurial folk in the computer industry may view this
wrenching phone company adjustment with some satisfaction. But the
fact is that computer companies face a strategic reorientation as
radical as the telcos do. In a world where ever smarter terminals
require ever dumber communications, computer networks are as gorged
and glutted with smarts as phone company networks and even less
capacious. The nation's most brilliant nerds, commanding the 200
MIPS Silicon Graphics superstations or Mac Quadra multimedia power
plants, humbly kneel before the 50 kilobit lines of the Internet and
beseech the telcos to upgrade to 64 kilobit basic ISDN.
Now addicted to the use of transistors to solve the problems of
limited bandwidth, the computer industry must use transistors to
exploit the opportunities of nearly unlimited bandwidth. When
home-based machines are optimized for manipulating high resolution
digital video at high speeds, they will necessarily command what are
now called supercomputer powers. This will mean that the dominant
computer technology will emerge first not in the office market but in
the consumer market. The major challenge for the computer industry
is to change its focus from a few hundred million offices already
full of computer technology to a billion living rooms now nearly
devoid of it.
Cable companies possess the advantage of already owning dumb
networks based on the essentials of the all optical model of
broadcast and select-- of customers seeking wavelengths or
frequencies rather than switching circuits. Cable companies already
provide all the programs to all the terminals and allow them to tune
in to the desired messages. Uniquely in the world, U.S. cable firms
already offer a broadband pipe to ninety percent of American homes.
These coaxial cables, operating at one gigahertz for several hundred
feet, provide the basis for two way broadband services today. But
the cable industry cannot become a full service supplier of
telecommunications until it changes its self-image from a cheap
provider of one way entertainment services into a common carrier of
two way information. Above all, the cable industry cannot succeed in
the digital age if it continues to regard the personal computer as an
alien and irrelevant machine.
Analogous to the integrated circuit in its economic power, the
all optical network is analogous to the massively parallel computer
in its technical paradigm. In the late 1980s in computers, the
effort to make one processor function ever faster on a serial stream
of data reached a point of diminishing returns. Superpipelining and
superscalar gains hit their limits. Despite experiments with
Josephson Junctions, high electron mobility, and cryogenics, usable
transistors simply could not made to switch much faster than a few
Computer architects responded by creating machines with multiple
processors operating in parallel on multiple streams of data. While
each processor worked more slowly than the fastest serial processors,
thousands of slow processors in parallel could far outperform the
fastest serial machines. Measured by cost effectiveness, the
massively parallel machines dwarfed the performance of conventional
The same pattern arose in communications and for many of the
same reasons. In the early 1990s the effort to increase the number
of bits that could be time division multiplexed down a fiber on a
single frequency band had reached a point of diminishing returns.
Again the switching speed of transistors was the show stopper. The
architects of all optical networks responded by creating systems
which can use not one wavelength or frequency but potentially
thousands in parallel.
Again, the new systems could not outperform time division
multiplexing on one frequency. But all optical networks opened up a
vast vista of some 75 thousand gigahertz of frequencies potentially
usable for communications. That immense potential of massively
parallel frequencies left all methods of putting more bits on a
single set of frequencies look as promising as launching computers
into the chill of outer space in order to accelerate their switching
Just as the law of the microcosm made all terminals smart,
distributing intelligence from the center to the edges of the
network, so the law of the telecosm creates a network dumb enough to
accommodate the incredible onrush of intelligence on its periphery.
Indeed, with the one chip supercomputer on the way, manufacturable
for under a hundred dollars toward the end of the decade, the law of
the microcosm is still gaining momentum. The fibersphere complements
the promise of ubiquitous computer power with equally ubiquitous
What happens, however, when not only transistors but also wires
are nearly free? As Robert Lucky observes in his forward to Paul
Green's book, Many of us have been conditioned to think that
transmission is inherently expensive; that we should use switching
and processing wherever possible to minimize transmission. This is
the law of the microcosm. But as Lucky speculates, The limitless
bandwidth of fiber optics changes these assumptions. Perhaps we
should transmit signals thousands of miles to avoid even the simplest
processing function. This is the law of the telecosm: use bandwidth
to simplify everything else.
Daniel Hillis of Thinking Machines Corporation offers a similar
vision, adding to Lucky's insight the further assertion that
massively parallel computer architectures are so efficient that they
can overthrow the personal computer revolution. Hillis envisages a
powerplant computer model, with huge Thinking Machines at the center
tapped by millions of relatively dumb terminals.
All these speculations assume that the Law of the Telecosm
usurps the Law of the Microcosm. But in fact the two concepts
function in different ways in different domains.
Electronic transistors use electrons to control, amplify, or
switch electrons. But photonics differ radically from electronics.
Because moving photons do not affect one another on contact, they
cannot readily be used to control, amplify, or switch each other.
Compared to electrons, moreover, photons are huge: infrared photons
at 1550 or 1300 nanometers are larger than a micron across. They
resist the miniaturization of the microcosm. For computing, photons
are far inferior to electrons. With single electron electronics now
in view, electrons will keep their advantage. For the foreseeable
future, computers will be made with electrons.
What are crippling flaws for photonic computing, however, are
huge assets for communicating. Because moving photons do not collide
with each other or respond to electronic charges, they are inherently
a two way medium. They are immune to lightning strikes,
electromagnetic pulses, or electrical power surges that destroy
electronic equipment. Virtually noiseless and massless pulses of
radiation, they move as fast and silently as light.
Listening to the technology, as Caltech prophet Carver Mead
recommends, one sees a natural division of labor between photonics
and electronics. Photonics will dominate communications and
electronics will dominate computing. The two technologies do not
compete; they are beautiful complements of each other.
The law of the microcosm makes distributed computers (smart
terminals) more efficient regardless of the cost of linking them
together. The law of the telecosm makes dumb and dark networks more
efficient regardless of how numerous and smart are the terminals.
Working together, however, these two laws of wires and switches impel
ever more widely distributed information systems.
It is the narrow bandwidth of current phone company connections
that explains the persistence of centralized computing in a world of
distributed machines. Narrowband connections require smart
interfaces and complex protocols and expensive data. Thus you get
your online information from only a few databases set up to
accommodate queries over the phone lines. You limit television
broadcasting to a few local stations. Using the relatively
narrowband phone network or television system, it pays to concentrate
memory and processing at one point and tap into the hub from
thousands of remote locations.
Using a broadband fiber system, by contrast, it will pay to
distribute memory and services to all points on the network.
Broadband links will foster specialization. If the costs of
communications are low, databases, libraries, and information
services can specialize and be readily reached by customers from
anywhere. On line services lose the economies of scale that lead a
firm such as Dialog to attempt to concentrate most of the world's
information in one set of giant archives.
By making bandwidth nearly free, the new integrated circuit of
the fibersphere will radically change the environment of all
information industries and technologies. In all eras, companies tend
to prevail by maximizing the use of the cheapest resources. In the
age of the fibersphere, they will use the huge intrinsic bandwidth of
fiber, all 25 thousand gigahertz or more, to replace nearly all the
hundreds of billions of dollars worth of switches, bridges, routers,
converters, codecs, compressors, error correctors, and other devices,
together with the trillions of lines of software code, that pervade
the intelligent switching fabric of both telephone and computer
The makers of all this equipment will resist mightily. But
there is no chance that the old regime can prevail by fighting cheap
and simple optics with costly and complex electronics and software.
The all optical network will triumph for the same reason that
the integrated circuit triumphed: it is incomparably cheaper than the
competition. Today, measured by the admittedly rough metric of MIPS
per dollar, a personal computer is more than one thousand times more
cost effective than a mainframe. Within 10 years, the all optical
network will be millions of times more cost effective than electronic
networks. Just as the electron rules in computers, the photon will
rule the waves of communication.
The all optical ideal will not immediately usurp other
technologies. Vacuum tubes reached their highest sales in the late
1970s. But just as the IC inexorably exerted its influence on all
industries, the all optical technology will impart constant pressure
on all other communications systems. Every competing system will
have to adapt to its cost structure. In the end, almost all
electronic communications will go through the wringer and emerge in
This is the real portent of the dark fiber case wending its way
through the courts. The future of the information age depends on the
rise of dumb and dark networks to accommodate the onrush of ever
smarter electronics. Ultimately at stake is nothing less than the
future of the computer and communications infrastructure of the U.S.
economy, its competitiveness in world markets, and the consummation
of the age of information. Although the phone companies do not want
to believe it, their future will be dark.
E-Mail Fredric L. Rice / The Skeptic Tank