Even people not in the field are well aware of the huge excitement about vertical-cavity surface-emitting lasers (VCSELs) that has developed over the past few years.1–5 The major reasons include their compatibility with wafer level manufacture and testing and their low numerical aperture beam that facilitates easy output coupling and packaging. These lasers are naturally formed in two-dimensional arrays, have low active volumes for low threshold, and are generally single frequency. Such characteristics make them excellent candidates for integration with electronics, and/or in two-dimensional or one-dimensional arrays for either free-space or fiber-ribbon optical interconnection. The single- frequency characteristic may also put off the need for switching from AlGaAs/GaAs 0.85-μm or InGaAs/GaAs 0.98-μm technology to InGaAsP/InP 1.3-μm technology for reduced dispersion in data links.
© 1991 Optical Society of AmericaPDF Article