Optical Networking Best Practices Handbook - Hardcover

Vacca, John R.

Hardcover

ISBN 10: 0471460524 ISBN 13: 9780471460527

Publisher: Wiley-Interscience, 2006

Synopsis

Optical Networking Best Practices Handbook presents optical networking in a very comprehensive way for nonengineers needing to understand the fundamentals of fiber, high-capacity, high-speed equipment and networks, and upcoming carrier services. The book provides a practical understanding of fiber optics as a physical medium, sorting out single-mode versus multi-mode and the crucial concept of Dense Wave-Division Multiplexing.

About this title

About the Author

JOHN R. VACCA, MS, MBA, is an information technology consultant and internationally known author. He has authored more than forty books and hundreds of articles in a wide range of technologies, including telecommunications, software, intelligence systems, and networks. His book The World's 20 Greatest Unsolved Problems was named one of Amazon.com's Best Books of 2004. Mr. Vacca was also a configuration management specialist, computer specialist, and the computer security official (CSO) for NASA's space station program (Freedom) and the International Space Station Program, from 1988 until his early retirement from NASA in 1995. Additionally, he is also an Independent online book reviewer and was one of the security consultants for the MGM movie Antitrust.

From the Back Cover

A step-by-step approach to everything you need to know about optical networking

From the fundamentals to advanced science to the most promising R&D, this book describes and illustrates how optical networking technology works. The author explains the underlying concepts, demystifies buzzwords and jargon, and instills a practical understanding of technologies and solutions, all without resorting to excessive detail. Not only do readers come to understand the current state of the technology, but they also gain valuable insight into the future of optical networking.

Following a discussion of the fundamentals of communications, the author breaks the topic down into logical components, including:

• Fiber optics, carrier networks, optical networking equipment, and broadband services
• How glass fiber is used as a physical medium for communications and how light is used to represent information
• Comparison of single- and multi-mode fiber and vendors
• Concept of fiber rings, including the two principal strategies that carriers use to organize capacity: traditional SONET/SDH channels and newer IP/ATM bandwidth on demand services
• Latest wave of promising new equipment, configurations, and services, including Gig-E services, dark fiber, managed IP services, and virtual private networks (VPNs)

Case studies, examples, and projects help readers understand how to install, configure, and troubleshoot optical networking technologies. A glossary at the end of the book defines terms and acronyms.

With this handbook, readers come to understand why optical technologies are viewed as the best solution to meet ever-growing capacity demands. By building knowledge from a solid foundation of the basics, it is not only appropriate for network engineers, managers, and consultants, but also for any professional who needs to understand how optical networking works.

From the fundamentals to advanced science to the most promising R&D, this book describes and illustrates how optical networking technology works. The author explains the underlying concepts, demystifies buzzwords and jargon, and instills a practical understanding of technologies and solutions, all without resorting to excessive detail. Not only do readers come to understand the current state of the technology, but they also gain valuable insight into the future of optical networking.

Following a discussion of the fundamentals of communications, the author breaks the topic down into logical components, including:

• Fiber optics, carrier networks, optical networking equipment, and broadband services
• How glass fiber is used as a physical medium for communications and how light is used to represent information
• Comparison of single- and multi-mode fiber and vendors
• Concept of fiber rings, including the two principal strategies that carriers use to organize capacity: traditional SONET/SDH channels and newer IP/ATM bandwidth on demand services
• Latest wave of promising new equipment, configurations, and services, including Gig-E services, dark fiber, managed IP services, and virtual private networks (VPNs)

Case studies, examples, and projects help readers understand how to install, configure, and troubleshoot optical networking technologies. A glossary at the end of the book defines terms and acronyms.

With this handbook, readers come to understand why optical technologies are viewed as the best solution to meet ever-growing capacity demands. By building knowledge from a solid foundation of the basics, it is not only appropriate for network engineers, managers, and consultants, but also for any professional who needs to understand how optical networking works.

Excerpt. © Reprinted by permission. All rights reserved.

Optical Networking Best Practices Handbook

By John R. Vacca

John Wiley & Sons

Copyright © 2006 John R. Vacca
All right reserved.
ISBN: 978-0-471-46052-7

Chapter One

Optical Networking Fundamentals

Throughout the past decade, global communications traffic in both voice and data has grown tremendously. Communications bandwidth capacity and geographic coverage have been substantially expanded to support this demand. These tremendous advances have been enabled by optical signals sent over fiber optics networks. However, the growth in tele- and data-communications traffic is just beginning. People are gaining exposure to a new world of choices and possibilities as an increasing number of them access the Internet via broadband. Streaming audio, teleconferencing, video-on-demand, and three-dimensional (3-D) virtual reality are just a few of the applications. Optical networking, with its inherent advantages, will be the key in making this new world of communications possible.

But how did optical networking come about in the first place? Let us take a brief look at the history of fiber optics.

1.1 FIBER OPTICS: A BRIEF HISTORY IN TIME

Very little is known about the first attempts to make glass. The Roman historian Pliny attributed it to Phoenician sailors. He recounted how they landed on a beach, propped a cooking pot on some blocks of natron that they were carrying as cargo, and made a fire over which to cook a meal. The sand beneath the fire melted and ran in a liquid stream that later cooled and hardened into glass, to their surprise.

Daniel Colladon, in 1841, made the first attempt at guiding light on the basis of total internal reflection in a medium. He attempted to couple light from an arc lamp into a stream of water. A large metal tube was filled with water and the cork removed from a small hole near the bottom, demonstrating the parabolic form of jets of water. A lamp placed opposite the jet opening illustrated total internal reflection. John Tyndall, in 1870, demonstrated that light used internal reflection to follow a specific path. Tyndall directed a beam of sunlight at a path of water that flowed from one container to another. It was seen that the light followed a zigzag path inside the curved path of the water. The first research into the guided transmission of light was marked by this simple experiment.

In 1880, William Wheeling patented this method of light transfer, called piping light. Wheeling believed that by using mirrored pipes branching off from a single source of illumination (a bright electric arc), he could send light to many different rooms in the same way that water, through plumbing, is carried within and throughout buildings. However, the concept of piping light never caught on due to the ineffectiveness of Wheeling's idea and to the concurrent highly successful introduction of Edison's incandescent lightbulb.

Also in 1880, Alexander Graham Bell transmitted his voice as a telephone signal through about 600 feet of free space (air) using a beam of light as the carrier (optical voice transmission)-demonstrating the basic principle of optical communications. He named his experimental device the photophone. In other words, the photophone used free-space light to carry the human voice 200 meters. Specifically placed mirrors reflected sunlight onto a diaphragm attached within the mouthpiece of the photophone. A light-sensitive selenium resistor mounted within a parabolic reflector was at the other end. This resistor was connected to a battery that was in turn wired to a telephone receiver. As one spoke into the photophone, the illuminated diaphragm vibrated, casting various intensities of light onto the selenium resistor. The changing intensity of light altered the current that passed through the telephone receiver, which then converted the light back into speech. Bell believed this invention was superior to the telephone because it did not need wires to connect the transmitter to the receiver. Today, free-space optical links find extensive use in metropolitan applications. Bell went on to invent the telephone, but he always thought the photophone was his greatest invention.

1.1.1 The Twentieth Century of Light

The first fiber optics cable was created by German medical student Heinrich Lamm in 1930. He was the first person to assemble a bundle of optical fibers to carry an image. Lamm's goal was to look inside inaccessible parts of the body. He reported transmitting the image of a lightbulb during his experiments.

In the second half of the twentieth century, fiber-optic technology experienced a phenomenal rate of progress. With the development of the fiberscope, early success came during the 1950s. This image-transmitting device, which used the first practical all-glass fiber, was concurrently devised by Brian O'Brien at the American Optical Company and Narinder S. Kapany (who first coined the term fiber optics in 1956) and colleagues at the American College of Science and Technology in London. Early on, transmission distances were limited because all-glass fibers experienced excessive optical loss-the loss of the light signal as it traveled the fiber.

So, in 1956, Kapany invented the glass-coated glass rod, which was used for non-telecommunications applications. By providing a means of protecting the beam of light from environmental obstacles, the glass-coated glass rod helped eliminate the biggest obstacle to Alexander Graham Bell's photophone.

In 1958, Arthur L. Schawlow and Charles H. Townes invented the laser and published "Infrared and Optical Masers" in the American Physical Society's Physical Review. The paper describes the basic principles of light amplification by stimulated emission of radiation (laser), initiating this new scientific field.

Thus, all the preceding inventions motivated scientists to develop glass fibers that included a separate glass coating. The innermost region of the fiber, or core, was used to transmit the light, while the glass coating, or cladding, prevented the light from leaking out of the core by reflecting the light within the boundaries of the core. This concept is explained by Snell's law, which states that the angle at which light is reflected is dependent on the refractive indices of the two materials-in this case, the core and the cladding. As illustrated in Figure 1.1, the lower refractive index of the cladding (with respect to the core) causes the light to be angled back into the core.

The fiberscope quickly found applications in the medical field as well as in inspections of welds inside reactor vessels and combustion chambers of jet aircraft engines. Fiberscope technology has evolved over the years to make laparoscopic surgery one of the great medical advances of the twentieth century.

The next important step in the establishment of the industry of fiber optics was the development of laser technology. Only the laser diode (LD) or its lower-power cousin, the light-emitting diode (LED), had the potential to generate large amounts of light in a spot tiny enough to be useful for fiber optics. As a graduate student at Columbia University in 1957, Gordon Gould popularized the idea of using lasers. He described the laser as an intense light source. Charles Townes and Arthur Schawlow at Bell Laboratories supported the laser in scientific circles shortly thereafter.

Lasers went through several generations of development, including that of the ruby laser and the helium-neon laser in 1960. Charles Kao proposed the possibility of a practical use for fiber-optic telecommunication. Kao predicted the performance levels that fiber optics could attain and prescribed the basic design and means to make fiber optics a practical and significant communications/transmission medium. Semiconductor lasers were first realized in 1962. Today, these lasers are the type most widely used in fiber optics.

Because of their higher modulation frequency capability, lasers as important means of carrying information did not go unnoticed by communications engineers. Light has an information-carrying capacity 10,000 times that of the highest radio frequencies in use. However, because it is adversely affected by environmental conditions such as rain, snow, hail, and smog, lasers are unsuited for open-air transmissions. Working at the Standard Telecommunication Laboratory in England in 1966, Charles Kao and Charles Hockham (even though they were faced with the challenge of finding a transmission medium other than air) published a landmark paper proposing that the optical fiber might be a suitable transmission medium if its attenuation could be kept under 20 decibels per kilometer (dB/km). Even for this attenuation, 99% of the light would be lost over just 3300 feet. In other words, only 1/100th of the optical power transmitted would reach the receiver. Optical fibers exhibited losses of 1000 dB/km or more at the time of their proposal. Intuitively, researchers postulated that these high optical losses were the result of impurities in the glass and not the glass itself. An optical loss of 20 dB/km was within the capability of the electronics and optoelectronic components of the day.

Glass researchers began to work on the problem of purifying glass through the inspiration of Kao and Hockham's proposal. In 1970, Robert Maurer, Donald Keck, and Peter Schultz of Corning succeeded in developing a glass fiber that exhibited attenuation of less than 20 dB/km, the threshold for making fiber optics a viable technology. In other words, Robert Maurer and his team designed and produced the first optical fiber. Furthermore, the use of fiber optics was generally not available until 1970 when Robert Maurer and his team were able to produce a practical fiber. Experts at the time predicted that the optical fiber would be useable for telecommunication transmission only if glass of very high purity was developed such that at least 1% of the light remained after traveling 1 km (attenuation). This glass would be the purest ever made at that time.

Early work on fiber-optic light sources and detectors was slow and often had to borrow technology developed for other reasons. For example, the first fiber-optic light sources were derived from visible indicator LEDs. As demand grew, light sources were developed for fiber optics that offered higher switching speed, more appropriate wavelengths, and higher output power.

Closely tied to wavelength, fiber optics developed over the years in a series of generations. The earliest fiber-optic systems were developed at an operating wavelength of about 850 nm. This wavelength corresponds to the so-called first window in a silica-based optical fiber, which refers to a wavelength region that offers low optical loss. It is located between several large absorption peaks caused primarily by moisture in the fiber and Rayleigh scattering.

Because the technology for light emitters at this wavelength had already been perfected in visible indicator LEDs, the 850-nm region was initially attractive. Low-cost silicon detectors could also be used at the 850-nm wavelength. However, the first window became less attractive as technology progressed because of its relatively high 3-dB/km loss limit.

With a lower attenuation of about 0.5 dB/km, most companies jumped to the second window at 1310 nm. In late 1977, Nippon Telegraph and Telephone (NTT) developed the third window at 155 nm. It offered the theoretical minimum optical loss for silica-based fibers, about 0.2 dB/km. Also in 1977, AT&T Bell Labs scientists' interest in lightwave communication led to the installation of the first lightwave system in an operating telephone company. This installation was the world's first lightwave system to provide a full range of telecommunications services-voice, data, and video-over a public switched network. The system, extending about 1.5 miles under downtown Chicago, used glass fibers that each carried the equivalent of 672 voice channels.

In 1988, installation of the first transatlantic fiber-optic cable linking North America and Europe was completed. The 3148-mile cable can handle 120,000 telephone calls simultaneously.

Today, systems using visible wavelengths near 660 nm, 850 nm, 1310 nm, and 1550 nm are all manufactured and deployed along with very low-end short-distance systems. Each wavelength has its advantages. Longer wavelengths offer higher performance, but always come with higher costs. The shortest link lengths can be handled with wavelengths of 660 or 850 nm. The longest link lengths require 1550-nm wavelength systems. A fourth window, near 1625 nm, is being developed. While it is not a lower loss than the 1550-nm window, the loss is comparable, and it might simplify some of the complexities of long-length, multiple-wavelength communications systems.

1.1.2 Real World Applications

Initially, the U.S. military moved quickly to use fiber optics for improved communications and tactical systems. In the early 1970s, the U.S. Navy installed a fiber-optic telephone link aboard the U.S.S. Little Rock. The Air Force followed suit by developing its airborne light optical fiber technology (ALOFT) program in 1976. Encouraged by the success of these applications, military R&D programs were funded to develop stronger fibers, tactical cables, ruggedized high-performance components, and numerous demonstration systems showing applications across the military spectrum.

Soon after, commercial applications followed. Both AT&T and GTE installed fiber-optic telephone systems in Chicago and Boston, respectively, in 1977. These successful applications led to an increase in fiber-optic telephone networks. Single-mode fibers operating in the 1310-nm, and later in the 1550-nm wavelength windows became the standard fiber installed for these networks by the early 1980s. Initially, the computer industry, information networks, and data communications were slower to embrace fiber. Today they too find use for a transmission system that has lighter-weight cable, resists lightning strikes, and carries more information faster and over longer distances.

Fiber-optic transmission was also embraced by the broadcast industry. The broadcasters of the Winter Olympics in Lake Placid, New York requested a fiber-optic video transmission system for backup video feeds in 1980. The fiber-optic feed, because of its quality and reliability, soon became the primary video feed, making the 1980 Winter Olympics the first fiber-optic television transmission. Later, fiber optics transmitted the first ever digital video signal at the 1994 Winter Olympics in Lillehammer, Norway. This application is still evolving today.

The U.S. government deregulated telephone service in the mid-1980s, which allowed small telephone companies to compete with the giant, AT&T. Companies such as MCI and Sprint quickly went to work installing regional fiber-optic telecommunications networks throughout the world. These companies laid miles of fiber-optic cable, allowing the deployment of these networks to continue throughout the 1980s by taking advantage of railroad lines, gas pipes, and other natural rights of way. However, this development created the need to expand fiber's transmission capabilities.

Bell Labs transmitted a 2.5-Gb/s (gigabits per second; giga means billion) signal over 7500 km without regeneration in 1990. For the lightwave to maintain its shape and density, the system used a soliton laser and an erbium-doped fiber amplifier (EDFA). In 1998, they went one better as researchers transmitted 100 simultaneous optical signals-each at a data rate of l0 Gb/s for a distance of nearly 250 miles (400 km). In this experiment, dense wavelength-division multiplexing (DWDM) technology, which allows multiple wavelengths to be combined into one optical signal, increased the total data rate on one fiber to one terabit per second ([10.sup.12] bits/s).

1.1.3 Today and Beyond

DWDM technology continues to develop today. Driven by the phenomenal growth of the Internet, the move to optical networking is the focus of new technologies as the demand for data bandwidth increases. As of this writing, nearly 800 million people have Internet access and use it regularly. Some 70 million or more households are wired. The World Wide Web already hosts over 5 billion web pages. And according to estimates, people upload more than 6.8 million new web pages every day.

(Continues...)

Excerpted from Optical Networking Best Practices Handbookby John R. Vacca Copyright © 2006 by John R. Vacca. Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Edition details

• Publisher: Wiley-Interscience
• Publication date: 2006
• Language: English
• ISBN 10: 0471460524
• ISBN 13: 9780471460527
• Binding: Hardcover
• Edition number: 1
• Number of pages: 512