Vertical-Cavity Surface-Emitters for Optoelectronic Integration (Invited Paper)

ABSTRACT Dramatic progress in surfe-emitting lasers in the past year has generated a lot of excitement in this area. Here we discuss recent results with strained-layer quantum-well lasers detailing low threshold current (0.6 mA) and narrow linewidth operation (85 MHz with a linewidth power product of 5MHz.mW). Theoretical analysis indicates the potentialfor increased power output without significant threshold increase. 1. INTRODUCTION The surface-emitting laser represents a new twist on the relatively old concept of the semiconductor laser. The basic change is to rotate the optical cavity 9O so that instead of being parallel to the wafer surface, it is perpendicular to thesurface. In this way the output will naturally be normal to the wafer surface and a new device is created: the vertical-cavitysurface-emitting laser (VCSEL).1 This simple conceptual change opens up a whole new range of processing options andapplication possibilities.Although it is conceptually simple to use a vertical cavity, the reduction to practice required overcoming severalproblems caused by the new cavity orientation. The most obvious structural difference between a VCSEL and an in-plane