Photonic crystal Vertical Cavity Surface Emitting Lasers (PC-VCSELs) - The future for high power single mode behaviour

Vertical Cavity Surface Emitting Lasers (VCSELs) have many advantages but their multi-mode transverse mode behaviour introduces problems for applications where output mode shape is important such as injection into fibre. Several groups world-wide have been investigating introducing photonic-crystal-hole patterns into the top-DBR to control the transverse modes. This has been observed to enhance the range of single mode behaviour but at the cost of low-output power. In addition there have been observations of altered modulation speed characteristics.