Vertical-cavity semiconductor optical amplifiers (VCSOAs) are interesting devices for a wide range of applications in optical communication systems. The vertical- cavity design gives these devices a number of advantages over in-plane devices, such as high coupling efficiency to optical fiber, low power consumption, small form factor, and the possibility of fabricating 2-D arrays on wafer. Furthermore, the technology allows for on-wafer testing and is compatible with low-cost manufacturing and packaging techniques
