Large-Scale Integrated Photonics for High-Performance Interconnects

Moore's Law has set great expectations that the performance of information technology will improve exponentially until at least the end of this decade. Although the physics of silicon transistors alone might allow these expectations to be met, the physics of the long metal wires that cross and connect packages almost certainly will not. Global-level interconnects incorporating large-scale integrated photonics fabricated on the same platform as silicon microelectronics hold the promise of revolutionizing computing by enabling parallel many-core and network switch architectures that combine unprecedented performance and ease of use with affordable power consumption. Over the last decade, remarkable progress has been made in research on low-power silicon photonic devices for interconnect applications, and CMOS-compatible fabrication technologies promise a "Moore's Law for photonics" that could completely change the economics of integrated optics. In this survey, photonic technologies amenable to large-scale CMOS integration are reviewed from the perspective of high-performance interconnects operating over distance scales of 1mm to 100m. An overview of the requirements placed on integrated optical devices by a variety of modern computer applications leads to discussions of active and passive photonic components designed to generate, guide, filter, modulate, and detect light in the telecommunication bands. Critical challenges and prospects for large-scale integration are evaluated with an emphasis on silicon-on-insulator as a platform for photonics.