Photonic devices for optical interconnects using epitaxial lift-off

Optical interconnects have the capability to improve upon the interconnect density and bandwidth limitations of electrical interconnects. In order to make these interconnects cost-effective, III-V emitters can be integrated with low-cost standard silicon circuitry. Light emitting diodes (LEDs) are the most easily fabricated semiconductor emitters, but LEDs have an inherently large spectral width and divergence angle, limiting their usefulness in communications applications.;To address the problem of the spectral width and divergence angle of LEDs, resonant-cavity-enhanced LEDs (RCELEDs) were studied and demonstrated. These emitters were formed by placing a conventional GaAs-based LED structure into a Fabry-Perot cavity. Epitaxial liftoff (ELO) with a transfer diaphragm was employed to deposit metal mirrors on both sides of the devices in the most easily fabricated RCELEDs, and LED structures with dielectric mirrors and semiconductor mirrors were examined and demonstrated. Properties such as divergence angle and outptut spectrum were modeled and compared to measured values. The integration onto silicon circuits of single RCELEDs as well as arrays of RCELEDs is also reported. Consideration was given to the crosstalk between emitter/detector channels and the speeds possible with RCELED structures.;Using similar integration techniques, a thin film detector was integrated onto a movable polyimide micromachine. This proof of concept micro-opto-mechanical system (MOMS) was demonstrated to address the problem of automatic coupling between fibers and optoelectronics. Variable coupling as a function of position was predicted and demonstrated.;Finally, recommendations are made for the further improvement in optical interconnects using vertical cavity surface emitting lasers (VCSELs). VCSELs offer significant improvements over LEDs in spectral purity, efficiency, and divergence angle. The use of ELO and the deposition of dielectric mirrors to form the VCSEL cavity have the capability to form a highly manufacturable, easily integrable emitter with characteristics greatly improved over LEDs.