Alight Photonics APS (Farum, DK) earned U.S. Patent 7,693,203 for VCSEL (Vertical-Cavity Surface-Emitting Laser) devices with single-mode output and optionally single polarization output. This device is characterized by lateral mode confinement by the PBG (Photonic Band-Gap) effect by shallow etching in a partial VCSEL top mirror. The PBG area encircles a MS-region (Mode-Shaping region), which is characterized by large longitudinal mode losses. The MS-region encircles the LA-region (Light Aperture region), which is characterized by low longitudinal mode losses. The MS-region does not contribute to the lateral mode-confinement to the LA-aperture, and the lateral modes confined by the PBG area.
The VCSEL is optimized for singlefundamental mode operation and gives an improved VCSEL design by providing basic structural details that allow large-aperture single-mode high-power operation, according to inventors Dan Birkedal, Svend Bischoff, Michael Juhl, Magnus Hald Madsen and Francis Pascal Romstad
Vertical-cavity surface-emitting lasers (VCSELs) have several advantages such as low-threshold, small size, on-wafer testability and high fiber coupling-efficiency. Single-mode VCSELs would be especially useful for applications such as data–(emission wavelength of .lamda.=850 nm) and telecommunication (.lamda.=1.3-1.7 .mu.m), if sufficient high single-mode output powers (5-20 mW) are extracted from a VCSEL.