Novel integration of substrate input/output vertical cavity lasers and resonant photodetectors

We present the first monolithic integration, without regrowth, of high-performance substrate input/output vertical-cavity lasers (VCLs) and resonant photodetectors that are compatible with flip-chip bonding and integrated microlenses. Integrated arrays of these devices are critical components for very dense bi-directional free-space optical interconnects. VCLs and resonant detectors fabricated side-by-side on the same chip have the same wavelength of operation to within <0.5 nm. The VCLs exhibit very low threshold currents, as low as 174 μA, and good differential efficiencies as high as 61%. The adjacent detectors are efficient, as demonstrated by responsivities of ∼0.4 A/W, with relatively broad optical bandwidths of ∼6 nm.