Intellectual Merit: The objective of this EAGER proposal is to investigate silicon based terahertz front end circuit design techniques, which will eventually lead to THz interconnects and solve the long-standing interconnect issue. The Chip-to-chip interconnect gap, which is between the ever-increasing bandwidth requirement and the limited number of I/O pins, has been a bottleneck for computer and embedded systems over decades and is getting more and more challenging with the increase of processing speed in advanced technologies. The THz spectrum holds great promise in the chip-to-chip interconnect area due to its ultra-wide bandwidth to support aggregate data rates orders of magnitude higher than existing interconnect capabilities. As the mainstream technologies for computer and embedded systems, silicon processes are the right technologies. However, the disadvantages of silicon processes, such as low supply voltages, large losses, and low cut-off frequencies, demand new design ideas to overcome these shortages. Therefore, this project will investigate two enabling techniques: (1) LO injected Schottky barrier diode (SBD) based mixing with high efficiency regenerative amplification receiving front end design, successfully demonstrated regenerative receiving structure; and (2) high power THz transmitter front end circuits, based on the proven high power generation scheme based on optimum signal conditions and low loss varactor-based modulation method. The circuit design techniques and methodologies are transformative, which can also apply to other high frequency circuits and systems in different processes. Broader Impacts: The success of silicon based THz front end circuits will eventually lead to THz interconnects, providing orders-of-magnitude better interconnect bandwidth density to address the bottleneck problem from interconnects. Therefore, it will support new computer architecture to meet the fast increasing data rate requirement in BIG DATA era. Furthermore, the successful technology developments will also open tremendous opportunities for a wide variety of important other THz applications by advancing THz technologies with high power, low noise and small form factors. For instance, it can enable portable THz devices for THz medical diagnosis for early disease detection; it can advance pharmaceutical and drug development through THz monitoring devices. These applications will not only advance scientific research, but also greatly benefit our daily lives and societies. The research results will be widely disseminated through international conferences and high impact journals. Both PIs are committed to engaging and retaining students from under-represented groups into engineering areas and will further extend outreach to local K-12 school students.
