Bias-free 1 Gb/s data transmission using high efficiency VCSELs

GaAs based selectively oxidized vertical-cavity surface-emitting lasers (VCSELs) with record high wallplug efficiencies of 57% emitting in the 820 to 860 nm wavelength regime are investigated as light sources for optical interconnection. Solid source molecular beam epitaxy with Carbon as p-type dopant is used for crystal growth. Multimode devices show CW output power up to 42 mW and stable operation from -80 up to +185°C. Efficient single-mode output power of more than two milliwatts is maximized by controlling the optical waveguiding that depends on the position of the 30 nm thin oxide aperture. Elliptically shaped current apertures are applied to stabilize output polarization. Data rates of 2.5 Gb/s with bit error rates smaller than 10^-11 are routinely achieved for transmission over several hundred meters of graded index multimode fiber. Bias-free modulation scheme is applied to vertical-cavity lasers for the first time and 1 Gb/s data links are established in this wavelength regime