Despite the prevalent use of light to carry information in modern computer networks, data centers, and telecommunications systems to support society's ever-increasing demand for bandwidth, limited progress has been made on the use of light to carry information between or on integrated circuit chips. Even less progress has been made on circuits that use light to process information. A key impediment to progress on true electronic-photonic integration has been the lack of a circuit element that operates in both the domain of light (photons) and electrons. An important breakthrough, made at the University of Illinois in Urbana-Champaign by Professors Nick Holonyak, Jr. and Milton Feng, is that certain types of transistors (the basic building blocks of electronic circuits) can be modified to generate and be acted on by light. These light-emitting transistors (LETs) and transistor lasers (TLs) will be used in this program to form true electronic-photonic digital logic circuits, and high-speed optical links both on and between chips. This technology is expected to dramatically improve the speed and energy efficiency of devices that process information, and to enable the commercial success of a new class of integrated circuits at the forefront of performance. Education and outreach activities will introduce undergraduates and high school teachers to a new technology based on light, renewing excitement in STEM-related fields and the creating the promise for a future career in electronic-photonic circuit engineering.
The technical work in this program is focused on bringing into existence a basic electronic-photonic circuit that can be used as the core building block for ultra-energy-efficient electronic-photonic computing systems. A multidisciplinary team has been assembled with expertise that spans the areas of semiconductor physics, materials and device processing, device design, high-speed circuits, and computer architecture to attack a variety of technical challenges and create a viable technology platform. At the fundamental level, physics-based models will be developed for the devices to optimize them for electronic and photonic functionality and predict their performance in an electronic-photonic circuit. In tandem, devices and circuits will be fabricated and characterized to optimize their performance and to improve the device models. Incorporating these devices and circuits into systems with conventional silicon circuits will require the development of scalable processing technologies that allow the formation of electronic-photonic "islands" embedded within silicon chips along with the electronic and photonic interconnects within and between these islands. Finally, architectures will be developed at the chip and system level that make optimal use of the functionality provided by these electronic-photonic logic circuits.
