Hybrid integration of VCSEL's to CMOS integrated circuits

摘要

Three hybrid integration techniques for bonding vertical-cavitynsurface-emitting lasers (VCSELs) to CMOS integrated circuit chips havenbeen developed and compared in order to determine the optimum method ofnfabricating VCSEL based smart pixels for optical interconnects andnfree-space optical processing. Each of the three bonding techniques usedndifferent ways of attaching the VCSEL to the integrated circuit andnmaking electrical contacts to the n- and p-mirrors. All three techniquesnremove the substrate from the VCSEL wafer leaving an array of individualnVCSELs bonded to individual pixels. The 4×4 and/or 8×8narrays of bonded VCSELs produced electrical and optical characteristicsntypical of unbonded VCSELs. Threshold voltages down to 1.5 V and dynamicnresistance as low as 30 Ω were measured, indicating goodnelectrical contact was obtained. Optical power as high as ~10 mW for anVCSEL with a 20-Μm aperture and 0.7 mW with a 6-Μm aperture werenobserved. The VCSELs were operated at 200 Mb/s (our equipment limit)nwith the rise and fall times of the optical output <1 nS