Wavelength-division multiplexed optical interconnects using monolithic wavelength-graded VCSEL and resonant photodetector arrays

Monolithic wavelength-graded vertical-cavity surface-emitting laser (VCSEL) and wavelength-selective resonance enhanced photodetector (REPD) arrays have been developed for use in wavelength-division multiplexed (WDM) optical interconnect architectures. The aim is to achieve a cost-effective wavelength-multiplexed optical interconnect that can carry a large amount of data over longer distances using a single optical fiber. A controllable means for producing wavelength-graded VCSEL and REPD arrays is described, based on the topography-controlled MOCVD growth on a patterned substrate. This technique allows the growth rate of all the epilayers to be scaled, thereby providing closer tracking of the reflectance peak and the gain peak and resulting in more uniform device characteristics. VCSELs and REPDs have been monoliothically integrated using the same epilayer structure and the same growth technique. This paper focuses on (1) the characteristics of oxide-confined multi-wavelength VCSEL arrays, (2) the design and comparison of optimized REPD structures at 850 nm and at 980 nm, and (3) wavelength multiplexing and demultiplexing using VCSEL and REPD arrays.