Overview

The 1980s saw an explosion in semiconductor lasers. The sheer numbers sold overwhelm all other types worldwide unit sales passed 20 million a year in 1988, compared to less than half a million of all other lasers combined ( Lasers & Optronics, 1990). The technology has advanced dramatically, with major advances in laser power, efficiency, speed, bandwidth, and wavelength range.

The first semiconductor lasers were developed in 1962, when three groups independently and nearly simultaneously demonstrated gallium arsenide diode lasers (Hall, 1976; Hecht, 1991). However, it was nearly a decade before researchers at Bell Laboratories and in the Soviet Union made the first semiconductor lasers able to produce a continuous beam at room temperature. The pace of development has accelerated since then, and semiconductor lasers have found many applications, including fiber-optic communications, compact-disk audio players, and laser printers.

Semiconductor lasers represent a large family of devices, with many different structures, made of a variety of materials. The variety is too large to cover in a single chapter, so it is grouped in Chaps. 18 to 21. This chapter is devoted to internal structures in commercial use and in development. These structures are common to most major semiconductor material systems, although certain structures are used only in certain materials. They are fundamental to understanding the discussions of specific semiconductor materials in Chaps. 19 to 21.

Chapter 19 covers short-wavelength semiconductor lasers, loosely defined as types emitting wavelengths shorter than about 1000 nanometers (nm). The principal members of this family have...