Perhaps one of the most anticipated events in optoelectronics occurred in January this year with the announcement by Nichia Chemicals in Japan that a "blue" laser diode with a 10,000-hour lifetime was being made commercially available in production quantities. Much has been said about the huge market potential of a blue-emitting semiconductor laser, with optical data storage being the most prominent application example. In this case, the relatively short wavelength (~ 400 nm) will lead to a significant increase in the capacity of optical storage systems. The market demand for such systems is already so large that it overshadows almost all other laser diode markets except telecommunications (see Laser Focus World, Feb. 1999, p. 52). In fact, many other applications will derive significant benefit from commercial availability of blue laser diodes, but the small size of these markets compared to data storage has left them in relative obscurity. These applications range from printing to biomedical instrumentation. And configuring these blue devices in an external-cavity arrangement opens up even more possibilities, particularly for spectroscopists (see p. 69).
Growing Internet demands bandwidth
Meanwhile, the state of the telecommunications business was clear from the record attendance at this year`s Optical Fiber Communication conference in San Diego, CA, in February (see p. 15). The strength of this meeting reflects the ongoing ravenous demand for bandwidth, which will certainly not abate soon-according to Forrester Research (Cambridge, MA) the number of online Internet accounts in the USA will increase 170% from the current 28.7 million to a whopping 77.6 million by 2002. And the usage will become more sophisticated, placing additional demands on the underlying networks. Tunable diode lasers are one example of the technologies available to support these networks (see p. 77), another is a variety of specialty fibers (see p. 93).
Images constitute a growing component of Internet traffic, and opto electronics technologies are continually evolving to improve the capture, digitization, and display of images. Complementary metal oxide semiconductor (CMOS) sensors, for example, have developed to the point of providing a viable alternative to charge-coupled devices and can be fully integrated on a single chip with associated circuitry (see p. 101). For industrial applications such as inspection, digitized video images offer certain advantages as compared to their analog counterparts-one benefit, for example, is that they are easily stored in computer memory for forwarding and for comparison with related images (see p. 139).