High speed optical links are finding ever increasing uses in optical communications and signal processing applications. Currently available planar waveguide lasers used in these links suffer from a high insertion loss due to a mode mismatch between the fiber and the modulator and the inability to implement a 2D array configurations. The vertical cavity surface emitting lasers (VCSEL) currently under development at several U.S. labs address these problems. These VCSEL devices consists of a quantum well Fabry-Perot cavity sandwiched between n and p doped high reflectivity mirrors. Vertical cavity lasers, however suffer from a high contact resistance due to a doughnut shape top electrode. This leads to increased heat and current crowding in the laser. We propose to eliminate this problem by depositing a transparent top electrode made from single crystal GaN. GaN is transparent to IR and visible and forms a ohmic contact to heavy doped GaAs. The Phase I program will determine if the VCSEL is damaged during the GaN deposition and measure the improvement in the top contact resistance. This will be followed by developing 2D fiber pigtailed VCSEL modules with monolithic detectors in Phase II. Anticipated Benefits: The proposed VCSEL modules and the developed technology form the basis of several high speed modulator, laser and optical interconnect devices. These offer unique system architectural possibilities for future DOD and commercial systems.
