Graphene-Silicon Photonics for Extreme Sensitivity, Cryogenic-Room Temperature Dense WDM Interconnects

Short work statement Funds are provided to develop new deposition and fabrication for graphene containing silicon photonic devices, proposed to convert digital superconducting logic pulses (bits) into WDM modulation of an optical carrier. Approach The approach is to focus on optimizing the geometry and materials fabrication technology for building electro-optical modulators from the vantage point of requiring as little energy dissipation as possible in the 4K environment. Graphene enhanced, silicon micro-ring resonators will be the focus. While current devices use wet transferred graphene, thin film growth in situ of the graphene will be developed. Advanced electromagnetic simulation tools will be calibrated against experiments and used to optimize the device geometry. Temperature dependences of the relevant materials properties will be measured and incorporated. Parasitic energy dissipation mechanisms, particularly those related to modal volume at the fiber to Si substrate interfaces will be worked. Surface defect and adsorbate effects on the grapheneÕs electrical properties will be a focus. Objective The objective of this effort is to further develop and optimize graphene ring resonators over silicon nitride waveguides to achieve 3 or more orders of magnitude decrease in the energy cost per bit of electro-optical modulators, when those modulators are operated at 4K and driven by superconducting electronic return to zero logic. This fundamental materials research will, if successful, be pivotal in efforts to translate the 6 orders of magnitude switching energy advantage of superconducting digital and mixed signal electronics over silicon processors into lower energy cost, more compact and lighter general purpose and digital signal processing systems for naval applications. Overall Merit and ONR Mission/Relevance The assembled team is highly ideal for this effort. Dr. Michal LipsonÕs world leading research on nanoscale silicon photonics established the ability to manipulate light on-chip and is widely recognized as enabling on-chip optical system integration, including importantly the applications of optical interconnects pursued in this effort. Dr. LipsonÕs honors and awards include Macarthur fellow, Blavatkink Award, IBM Faculty Award, and NSF Early Career Award. She is a fellow of the OSA (Optical Society of America) and of IEEE. Dr. Lipson is currently the Higgins Professor of Electrical Engineering at Columbia University and is listed on over 20 patents. Dr. Keren Bergman is a leading researcher on optical interconnection networks for advanced computing systems. She serves as Interconnect Thrust advisor for the NSAÕs Center for Exceptional Computing and was a co-author of the DARPA Exascale Study Group Report. She has led the field in developing and utilizing nanoscale silicon photonics to provide a dramatic reduction in power expended on intrachip global communications. Dr. Bergman is currently the Charles Batchelor Professor and Chair of Electrical Engineering at Columbia University where she also directs the Lightwave Research Laboratory (LRL). Dr. Bergman won a National Science Foundation CAREER award, was an ONR YIP and has also won awards from CalTech, and IBM. Dr. Bergman is a Fellow of the Institute of Electrical and Electronic Engineers (IEEE) and of the Optical Society of America (OSA). Dr. Lipson will coordinate the effort which will occur at the facilities of Columbia ,Cornell and CUNY. This effort is doing the foundational research needed for naval platforms to be able to utilize both the extremely high wideband sensitivity of superconducting analog to digital converters and the significant volume, weight and hopefully power savings of superconducting server class computers. The latter would reduce the cost of having mobile platforms while the former is key to affordable multifunctionality of rf systems, needed to maintain the future pace of battle.