0.85-mu m Vertical-cavity surface-emitting laser array grown on GaAs and AlGaAs substrates by metal organic chemical vapor deposition

We report very uniform characteristics of 0.85 mu m vertical-cavity surface-emitting lasers (VCSELs) array grown by metal organic chemical vapor deposition (MOCVD) at a high growth rate. For a 16 mu m diameter pixel, the threshold current is 3.29 +/- 0.25 mA and the emission wavelength is 850.9 +/- 0.6 nm at 6 mA along the 8 x 8 pixels. Considering the offset gain and Al content of the spacer layer, the threshold voltage is 2.1 V. By growing VCSELs on an AlGaAs substrate, we were able to acheive a bottom-emitting 0.85 mu m VCSEL array where all elements operated successfully. We also discuss the modulation speed limit and the thermal interference problem of VCSEL arrays. The modulation limit is shown to depend on the capacitance and resistance (CR) time constant of electrodes, and the maximum temperature increase is about 15 degrees C around the center of the chip when the other pixels are driven at the threshold current.