Planar Photonic Integration of VCSEL-Based Wavelength Division Multiplexed Optoelectronic Arrays

Vertical-cavity surface-emitting lasers (VCSELs) have a small form factor, low drive current, low power dissipation, and natural two-dimensional integrability. However, the surface-normal cavity of the VCSEL makes it difficult to integrate with in-plane waveguides and other optoelectronic components to form planar photonic circuits. This obstacle can be overcome by embedding an optical waveguide within the resonance cavity of the VCSEL, and utilizing waveguide grating couplers (WGC) to diffract light from the VCSEL cavity into the waveguide (Louderback, 2005). Resonance-enhanced diffraction produces highly efficient optical coupling to the waveguide, which can combine (multiplex) the optical outputs from all VCSELs within the array and distribute (broadcast) their data contents to all nodes along the array in a highly integrated and compact manner.