InP-Based Long-Wavelength VCSELs and VCSEL Arrays

Long-wavelength, InP-based, vertical-cavity surface-emitting lasers with buried tunnel junction (LW-BTJ-VCSELs) and VCSEL arrays are presented. Emitting at the telecommunications wavelengths around 1.3 and 1.55 mum, these devices show high modulation bandwidth in excess of 10 GHz over a wide temperature range. Small-signal equivalent circuits for the parasitic and intrinsic response are given. Various data-transmission experiments are performed with data rates up to 12.5 Gb/s over different fiber channels. 1-D LW-BTJ-VCSEL arrays can be used in wavelength-division multiplexing systems for high bandwidth per fiber channel. 2-D high-speed arrays with 64 individually addressable channels are presented that are particularly suited for optical ultrabroadband interconnects. Furthermore, large-scale arrays are investigated for high-power applications. In a detailed investigation, we derive scaling rules considering the influence of aperture, array size, and pitch on laser power. At room temperature, optical output powers in the watt regime have been realized at 1.55 mum. Divergence angles are as low as 13deg-17deg full-width at half-maximum. Wall plug efficiencies in excess of 20% over a wide current range and high-temperature operation up to 80degC are obtained.