1.3 μm Optical Interconnect on Silicon: A Monolithic III-Nitride Nanowire Photonic Integrated Circuit

A feasible optical interconnect on a silicon complementary metal-oxide-semiconductor chip demands epitaxial growth and monolithic integration of diode lasers and optical detectors with guided wave components on a (001) Si wafer, with all the components preferably operating in the wavelength range of 1.3-1.55 μm at room temperature. It is also desirable for the fabrication technique to be relatively simple and reproducible. Techniques demonstrated in the past for having optically and electrically pumped GaAs- and InP-based lasers on silicon include wafer bonding, selective area epitaxy, epitaxy on tilted substrates, and use of quantum dot or planar buffer layers. Here, we present a novel monolithic optical interconnect on a (001) Si substrate consisting of a III-nitride dot-in-nanowire array edge emitting diode laser and guided wave photodiode, with a planar SiO₂/Si₃N₄ dielectric waveguide in between. The active devices are realized with the same nanowire heterostructure by one-step epitaxy. The electronic properties of the InN dot-like nanostructures and mode confinement and propagation in the nanowire waveguides have been modeled. The laser, emitting at the desired wavelength of 1.3 μm, with threshold current ∼350 mA for a device of dimension 50 μm × 2 mm, has been characterized in detail. The detector exhibits a responsivity ∼0.1 A/W at 1.3 μm. Operation of the entire optical interconnect via the dielectric waveguide is demonstrated.