Whats in store for diode arrays?

One year after C. Townes, N. Basov, and A. Prokhorov received the Nobel Prize in 1964 for developing the principles of the laser, N. Basov devoted his Nobel Prize Lecture to the physics and application of diode lasers [see Science 149, 821 (1965)]. He proposed that ultrafast optical logic gates might be built around diode lasers, keeping in mind future applications of diodes. It was thought to be a crazy idea back then, as diodes were operating at liquid-nitrogen temperatures only.

What`s in store for diode arrays?

Bistabilities and Nonlinearities in Laser Diodes

Hitoshi Kawaguchi, Artech House Inc., Boston, London, 1994, 379 pages.

One year after C. Townes, N. Basov, and A. Prokhorov received the Nobel Prize in 1964 for developing the principles of the laser, N. Basov devoted his Nobel Prize Lecture to the physics and application of diode lasers [see Science 149, 821 (1965)]. He proposed that ultrafast optical logic gates might be built around diode lasers, keeping in mind future applications of diodes. It was thought to be a crazy idea back then, as diodes were operating at liquid-nitrogen temperatures only.

At that time, I was finishing my Ph.D. at P. N. Lebedev Institute in Moscow, and N. Basov asked me to lead discussions on the theory and experiments with bistable laser diodes proposed by Lasher in 1964. A series of papers published about two and half decades ago described the phenomena in absorptive bistable laser diodes and optical logic gates based on them.

One can understand the excitement I felt when reviewing Kawaguchi`s book. First, the book is written clearly by an expert in the field, and the math is simple and sufficient. Each chapter is followed by a rather complete list of references. The organization of this book is as follows. The introduction covers briefly the historical perspective of diode lasers and functional devices based on them. Chapter 2 reviews the lasing principles, basic device structure, dynamic characteristics, and nonlinear phenomena of diode lasers.

Chapters 3 through 6 describe absorptive, dispersive, two-mode, and waveguiding bistable laser diodes. Self-pulsation, chaos, and modelocking in laser diodes are described in chapter 7; wavelength conversion, selection, and wavelength-selective detection in chapters 8 and 9; and applications for photonic switching such as soliton transmission systems, clock distribution, wavelength-division multiplexing systems, and optical switching networks are covered in chapter 10.

Finally, future prospects are discussed: quantum-wire and quantum-box diode lasers, surface-emitting lasers, and microcavity laser diodes. I list the full content of the book intentionally to show the breadth of the problems covered by author . This book summarizes information that is scattered in numerous papers. I would recommend it to engineers and scientists working in the field of optoelectronics. It could also serve as a textbook for graduate students.

The book is already very good, but it could be improved. The section 11.4 "Two dimensional array" should have more data devoted to VCSEL (vertical cavity surface-emitting laser) characterization, performance of which improved dramatically in the last few years. I would like to see future editions of the book describe the VCSEL array in more detail.

After nearly 25 years of research, we have come to understand the physics of bistable laser diodes and possible areas of application, and H. Kawaguchi demonstrates this convincingly in his book. Still, the question remains: when will we be able to buy a functional device based on an array of bistable diode lasers for massively parallel optical interconnections?

V. N. Morozov

Professor V. N. Morozov can be reached at the University of Colorado at Boulder, Optoelectronic Computing Systems Center, Boulder, Co, 80309-0525; e-mail: morozov@boulder.colorado.gifdu.

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