It was in 1962—almost 40 years ago—that the earliest reports of laser action in a semiconductor material were received. The first commercially available semiconductor diode laser followed in the 1970s. Subsequent development has brought longer lifetimes, more wavelengths, and across-the-board performance improvements; by 1999, according to this year's Annual Review and Forecast of the Laser Marketplace (see Laser Focus World; Jan. 00, p. 92), laser-diode revenues represented 64% of all lasers sold (up from 57% in 1996) and are projected to reach 69% this year. Furthermore, in terms of units sold, for the past several years these devices actually have accounted for about 99% of the total, which means most laser light is now produced directly or indirectly (via diode pumping) by semiconductor lasers. In fact, laser diodes have become so ubiquitous that almost no "traditional" laser application has escaped their influence, including some of the relatively high-power industrial ones. Given their importance, then, this month we introduce a new monthly series of tutorial-style articles by contributing editor Stephen J. Matthews that traces the development of these devices from their inception to the present day (see p. 81).
Matthews points out in his first article that the potential of semiconductor lasers for optical communications was recognized very early on and has driven much of the resulting development. The commercial introduction of vertical-cavity surface-emitting lasers (VCSELs) in 1996, for example, was made possible in part because of the high volumes associated with the telecom market—now, though, other applications can reap the benefits of that work (see p. 131). And it is almost inevitable that, as the sophistication of all these devices increases, so too does the complexity of characterizing their performance (see p. 139). At about the same time as the first diode laser was introduced, charge-coupled-device (CCD) detectors also were emerging. Since those early days in 1969, CCDs have evolved from primarily a data-storage device to address a wide range of detector and imaging applications. And most recently, high-end CCD-based cameras are often intended to be application-specific (see p. 101).
Looking forward for a moment, this month's cover shows an optical waveguide created in a glass substrate using ultrafast laser pulses. Materials processing is an important emerging application for femtosecond lasers (see p. 73). Meanwhile, the amazing demand for telecom bandwidth has pushed fiber Bragg gratings to the forefront of wavelength-division-multiplexing components so the routine production of them is becoming an increasingly significant issue (see p. 107).
P.S. The Laser Marketplace Seminar/Europe will be held in Frankfurt, Germany, on Wednesday June 28, 2000. The agenda includes an extensive review of worldwide laser markets for 1999 and forecasts for 2000. For more information contact Sharon MacLeod at [email protected].