Date of Award
Doctor of Philosophy (PhD)
For the first time, high-performance photonic devices and electronic-photonic systems-on-chip are monolithically integrated in an advanced CMOS microelectronics fabrication process. This includes a silicon optical resonator termed the "spoked-ring" cavity that meets the constraints of thin-SOI microelectronics CMOS processes and enables energy efficient modulators and thermally tunable filters. For low-loss fiber-to-chip optical coupling, a phased-array antenna concept is demonstrated, and the 45 nm CMOS microelectronics process is shown to support a near ideal implementation of the device using the crystalline silicon and polysilicon material layers that comprise the active region and gate, respectively, of the native MOSFET transistors.
The active devices and vertical grating couplers are implemented in large-scale electronic-photonic systems-on-chip to demonstrate a wavelength stabilized, microring-based chip-to-chip communications link and an 11-channel wavelength division multiplexed (WDM) transmitter. The link is shown to be robust against thermal environmental variations which is critical for operation in realistic systems. The chip-to-chip link is then used to demonstrate a CPU-to-memory communication link, the first demonstration of its kind. The first microprocessor with photonic I/O is demonstrated as part of this work, with substantial implications for computer architecture.
Advanced photonic device technology demonstrations, including photonic crystals, a quantum-correlated photon-pair source, an active photonic device platform in a 32 nm SOI node, and a 180 nm bulk silicon process, are presented to show the wide range of applications that monolithic integration could support in the future of photonics.
These results taken together show that monolithic integration directly into CMOS microelectronics processes does allow high performance photonics, and is a viable approach to build large-scale electronic-photonic systems with a realistic path to commercial technologies.
Wade, Mark T., "Devices and Systems-on-Chip for Photonic Communication Links in a Microprocessor" (2015). Electrical, Computer & Energy Engineering Graduate Theses & Dissertations. 139.