Free-Space Optical Interconnect Using Flip-Chip bonded, Microlensed Arrays of Monolithic Vertical Cavity Lasers and Resonant Photodetectors

摘要

A free-space optical link is demonstrated using monolithically integrated vertical-cavity lasers (VCLs) and resonant photodetectors. The devices have been integrated using a novel epitaxial structure that makes it possible to fabricate devices with through-the-substrate emission and detection using only post-growth processing [1]. Taking advantage of the substrate emitting/detecting architecture, we monolithically integrate microlenses on the substrate side of the devices and flip-chi bond arrays without via processes or substrate removal [2]. Figure 1 shows a scanning electron microscope image of such an array flip-chip bonded to co-planar transmission lines. The VCLs have threshold currents below 200μA with slope efficiencies above 60% and modulation bandwidths exceeding 89 GHz at 500 μA bias. The detectors have peak quantum efficiencies of 60% with full width at half maximum optical bandwidths of 7 nm and the same peak responsivity wavelength as the adjacent VCLs lasing wavelengths (to within 0.5 nm).