Progress on single mode VCSELs for data- and tele-communications

Single mode (SM) 850 nm vertical-cavity surface-emitting lasers (VCSELs) are suitable for error-free (bit error ratio <10(-12)) data transmission at 17-25 Gb/s at distances 2-0.6 km over 50 mu m-core multimode fiber (MMF). Reduced chromatic dispersion due to ultralow chirp of SM VCSELs under high speed modulation (up to 40 Gb/s) are responsible for the dramatic length extension. Good coupling tolerances of the SM devices to the MMF manifest their applicability for low cost optical interconnects. As the higher resonance frequency (up to 30 GHz) is reached at lower current densities in small aperture (3 mu m -diameter) devices the SM devices are also preferable due to reliability considerations.