Abstract :
The first coherent vertical cavity surface-emitting laser (VCSEL) array with the in-phase mode using a simple fabrication process has been demonstrated at the University of Illinois at Urbana-Champaign in the USA. The 2 × 2 VCSEL array was made using conventional fabrication processes that are already in use to manufacture millions of VCSELs, and photonic crystal coupling was used to control the cavity loss and achieve a stable beam mode. "An important advantage is the possibility to scale up the array size to coherently combine several tens to potentially thousands of VCSELs into a coherent array," said Professor Kent Choquette, Director of the Photonic Device Research Group. "Such high power low divergence laser arrays are of interest for optical pumping of solid state and/or fibre lasers at very specifi c emission wavelengths, as well as being directly used as high power laser sources for applications such as laser welding, LIDAR, and laser infrared illumination."
