Customer Reviews

Introduction to DWDM Technology: Data in a Rainbow

5 star:		(1)
4 star:		(1)
3 star:		(3)
2 star:		(0)
1 star:		(7)

 

 

I saw this book on display as I passed the SPIE booth at OFC'00 on Sunday after picking up my registration material for the show. I took the top copy from a stack of 12. By the time I finished leafing through the pages the stack was gone. They were selling like hotcakes. Scanning the book, I found plenty of equations (so I figured it must not be too superficial) and (I'm ashamed to say) the color figures particularly caught my attention. Always anxious to catch a new perspective, I put my plastic down and left the convention hall feeling pretty happy about the great new book I just purchased.

I started reading the book that evening, over dinner, and finished it four days later on the flight home from Baltimore to Portland. My earliest impressions were quickly shattered, however, as I realized less than ten pages into the book that it was not going to measure up to my earlier expectations.

One of the most prominent problems with this book is that the author seems to be continually confused regarding his audience. For example, on page 7 he plunks down Maxwell's equations with barely an explanation, and yet several sentences later he goes into considerable detail describing what is meant by phase, frequency, and wavelength of a wave. Clearly, if you can read Maxwell's equations without explanation the discussion about elementary attributes of waves is wholly unnecessary. On the other hand, if a person reading the book needs to be told what frequency is, then Maxwell's equations will look like meaningless gibberish.

Another surprising problem with the book are the many technical errors and typographical mistakes. I found these to be the most troublesome, since they can lead to real confusion on some important topics for anyone who is new to the topic of WDM. Here is an example from page 117:

"Optical amplifiers require electrical or optical energy to excite (pump-up) the state of electron-hole pairs. Energy is typically provided by injecting electrical current (in SOA: Figure 8.2) or optical light in the UV range (in EDFA)."

This isn't just a typographical error because the author repeats the mistake on page 119 where he says:

"The EDFA is stimulated by a higher optical frequency (in the UV range) laser source, known as the pump."

Anyone familiar with EDFA optical amplifiers used in telecommunications will immediately realize that this is wrong. EDFAs are pumped at 1480 nm or 980 nm (both in the near IR). They are not pumped in the UV. In fact, the author clearly states that "erbium ions may be excited by a number of optical frequencies - 514 nm, 532 nm, 667 nm, 800 nm, 980 nm, and 1480 nm." (see page 118). This is a good example of the misleading, false, and contradictory information that creeps into this book far too often, and is likely to cause a good deal of confusion for people new to WDM technology, and a good deal of aggravation for the rest. I could go on with other examples, but this should be adequate to prove the point.

Some of the book's problems are more annoying than dangerous. For example, the author introduces the reader to light using photometric units rather than the more commonly used (in telecom, anyway) radiometric units. The author also has a tendency to wander in his descriptions, introducing ideas out of sequence and repeating ideas that have been already developed. Overall, the book reads a little like crib notes, with some important subjects having their own bold-faced headings but only a sentence or two of discussion. One of the biggest shortfalls is the book's failure to address polarization mode dispersion. It devotes only one short description (in the whole book, as far as I can recall):

"This phenomenon (PMD) is not well understood or theoretically explained, although it is known and demonstrated via experiments." (see page 54).

Clearly, lots more could (and should) have been said about PMD in a book of this sort.

Reading this book I got the distinct impression that it was rushed to print too soon. The subject matter (DWDM) is good, and the book's organization is appropriate, it just needs to be polished a bit, filled in where the discussion is too truncated, and have the mistakes and typographical errors corrected. The plan and overall organization, though, are actually pretty nice. The book is organized into three parts. Part one is an overview of the nature of light and the interaction of photons with matter. Subjects include Snell's law, critical angle, diffraction, holography, polarization, and some really elementary discussions about nonlinear effects.

Part two deals with optical components, beginning with optical fiber, filters, gratings, demultiplexers, light sources, photodetectors, couplers, isolators, polarizers, optical cross-connects, and add-drop multiplexers. This sounds like a lot of ground to cover - and it is - but the author does it all in about 120 pages, so you can appreciate that none of the discussions goes into much detail.

Part three is devoted to different coding techniques, and describes return to zero, non-return to zero, ASK, PSK, and FSK formats. Part four describes the specifics of WDM, and in many respects it repeats what was said in part two. Part five summarizes current issues and research (something that I personally find problematical in a book, as it immediately dates it). The book comes with a long list of acronyms (a plus) and pretty complete references at the end of each section (also a plus). The index is also nicely done and complete.

Overall, though, this book is probably not worth your time or money. If you want a good introduction to modern telecommunications, I suggest "Optical Fiber Telecommunications III" (A and B) by Kaminow and Koch. These books are more expensive, but far more accurate and complete.

Duwayne Anderson, March 17, 2000

This book is filled with inaccurate physics, typographical errors, poorly drawn diagrams, and confusing explanations. I do not recommend it.

A top level overview of fiber communications technology. But glaring technical errors bring into question the accuracy of the entire text. Examples include errant claims that photons may be deflected by strong electric fields and that photons carry mass. Other examples abound.

Only 70 of the 250 pages are dedicated to DWDM technology directly. Full of conflicting and ambiguous comments. For instance the section on Arrayed Waveguide Grating states in two consectutive comments: >AWG's are temperature sensitive. To eliminate thermal drift... Next Comment: >AWG's operating in the wide temerature range (0-85C) have been reported. Most topics are treated rather lightly. Seems like a book put together in a hurry to cash in on the recent "Fiber" goldrush.

The book has good coverage, and will leave the reader with a decent overview of what's out there, but very little understanding of anything. While that seems like the point of such a book, it doesn't really make the book useful. This isn't popular physics--anybody who needs an overview of DWDM probably needs a little more than this tiny book can offer.

The other reviews about the book's low editing quality were right on. It has the feel of something produced with a laptop, one weekend and an inkjet.

This book presents a very methodical approach to the topic of DWDM and addresses the key technology points of: optics in general,optical components, coding, then a closer examination of DWDM itself. The text is peppered with helpful graphics and illustrations. Unfortunately, the book has been poorly proofed with numerous typographical and grammatical errors as well as a good number of technical errors. These last are a certain distraction to the novice reader.

The content is interesting.
It tries to focus on the basic concepts behind the various components used in DWDM.
The problem is the numerous errors and the incoherence throughout the book:
- notation varies;
- errors are flagrant and should have been easely corrected with a simple review;
- some fondamental errors of physics: the photon does not a mass!!!! (p. 8)

Should be reedited.

This book is filled with inaccurate physics, typographical errors, poorly drawn illustrations and confusing/misleading explanations. I do not recommend it.

It was a pleasant surprise to read this book. I decided to buy the book despite a 3 star rating because I needed to update myself quickly.

First I found the book full of nicely done and colorful diagrams that are easy to understand. The author succeeds in explaining fairly complex topics in simple enough words that someone like me with background in science and engineering but work in another field can grasp the concepts quite fast.

The book covers a wide range of the latest technologies so it is definitely a useful reference book for people looking to understand optical engineering. It may be too simple for readers who are already knowledgeable in optics. In that sense, I can actually see disappointment by them. But for managers and investors who want to know the subject enough to appreciate the technology-- but not to be an engineer or designer in the field-- this is very useful.

I used to write "introductory" books in another technical field with good review from managers and technicians. This book has accomplished that goal for me.

Too complicated with all the abbrevations and mathematical details not to understand for "non-scientists". Not everybody is an PhD!

Much better book is the following:
ISBN: 3895781746