CAREER: Towards Sustainable Computing with Carbon-Efficient Integrated Electro-Photonic Fabrics

PROJECT SUMMARY Overview Climate-changing carbon emissions from powering information and computing technologies (ICT) are projected to increase to 8% of worldwide carbon emissions over the next decade due to the explosion of computing required in everyday consumer electronic devices and systems. In the wake of this emergency, recent studies have shown that integrated electro-photonics (IEPh) based fabrics for communication and computing, compared to the conventional electronic fabrics, can endow substantially higher use-phase energy and carbon efficiency (up to 100× in some cases) to future computing hardware platforms. However, designing carbon-efficient computing hardware platforms is not merely about reducing the use-phase carbon emissions. It is also crucial to (1) minimize embodied carbon emissions due to hardware manufacturing and product infrastructure-related activities, (2) account for the area, yield, performance, and lifetime reliability of hardware components, and (3) follow universally accepted tenets of Reduce, Reuse, and Recycle. Meeting all these requirements, however, has not yet been possible for computing hardware platforms comprising IEPh-based fabrics. This is mainly because the existing tools and methods for modeling, analyzing, and optimizing overall carbon footprints (embodied + use-phase) focus on electronic fabrics-based computing platforms and do not factor in the critical impacts of challenging factors peculiar to the IEPh technology. These factors include deviation from the standard CMOS-based materials and fabrication processes, the complex physical design (based on the curvilinear geometry) of IEPh-based components, and lifetime reliability challenges due to high proneness to the fabrication nonuniformity, temperature variations, and aging effects. This project will present well-reasoned and synergistic research activities to address these fundamental shortcomings and ignite widespread research for sustainable computing hardware design using IEPh-based fabrics. This project will also create opportunities for industrial partnership, local outreach, diversity promotion, and curriculum innovation. Intellectual Merit This project will employ the principles of heterogeneity, reconfigurability, and recycling to design mixed- signal, multi-functional, and multi-lifespan IEPh-based fabrics for transceiver and accelerator architectures to transform sustainability, performance, resource utilization, and lifetime reliability. The overarching goal will be to reduce the impact of embodied energy and extend the operational lifetime of hardware fabrics to enhance the sustainability and carbon efficiency of computing systems. This project will result in (1) a framework, developed through proposed collaborations with industry partners, that factors in the critical impacts of yield, variations in fabrication-process and temperature, and aging effects for modeling the embodied and use-phase carbon footprints of IEPh-based transceiver and accelerator fabrics, (2) heterogeneous, mixed-signal, and carbon-efficient organizations of IEPh-based transceiver and accelerator fabrics with minimal carbon footprints and maximal lifespans, (3) methods to repurpose IEPh-based fabrics for multiple functionalities to minimize resource idle-time and embodied emissions, (4) cross-layer techniques to extend the reliable utilization of proposed IEPh-based transceiver and accelerator architectures across multiple lifespans, and (5) an extensive simulation framework for evaluation, validation, and comparison of different heterogeneous computing system architectures comprising the proposed IEPh- based fabrics, focusing on various important metrics of energy efficiency, carbon efficiency, performance, lifetime reliability, and resource utilization. Broader Impacts The outcomes of this project will ignite a wide spectrum of future research efforts. The outcomes of these research efforts will inform U.S.-based stakeholders of sustainable practices to follow for the design and manufacturing of IEPh-based fabrics and computing hardware platforms. This will in turn help the U.S. out- compete global competitors to emerge as the pioneer in sustainable computing design using IEPh-based fabrics. Moreover, this project will create novel educational materials using the newly developed tutorial videos and interactive simulation modules to provide students with a more tangible, hands-on approach to learning the fundamentals of integrated electro-photonics and sustainable computing hardware design. These videos and modules will be employed to (i) innovate curricula, (ii) promote community outreach, (iii) engage undergraduate students in supervised research, (iv) promote diversity by training STEM teachers of local middle schools that primarily serve underrepresented groups, through the existing NanoEducate program of Kentucky Multiscale (the Kentucky NSF NNCI node), and (v) train engineering faculty on the use of interactive modules for teaching, through the proposed partnership with Massachusetts Institute of Technology (MIT). Moreover, a Ph.D. student will be recruited from underrepresented groups in STEM for research training in close collaboration with researchers from CMC Microsystems and GlobalFoundries.