Nanophotonic circuits support strong confinement (SC) of light in wavelength-scale waveguides and resonators with long photon lifetimes. They raise the prospect of dense photonic integration on a chip, and of new device concepts with superior performance and novel functionality, based on unique device physics and topologies that become practical in this regime. Nanophotonics has potential to revolutionize current technology in communication, computation and energy conversion, by harnessing large optical bandwidth, high energy-efficiency designs, and all-optical feedback control. At the same time, major challenges to widespread assimilation of SC nanophotonics into mainstream technology have been their ultrasensitivity, and limited scalability and complexity.

In this talk, I first describe SC nanophotonic devices that successfully address the atomic-scale ultrasensitivity and scalability challenges by appealing to general physical principles in design. The first microring-resonator-based nanophotonic circuits with telecom-grade performance were demonstrated enabling chip-scale tunable optical add-drop multiplexers, a key component for ultrahigh-bandwidth agile optical networks, and on-chip interconnects. Novel device concepts are described that allow approaching the limits of bandwidth efficiency, including an errorless switch, polarization transparency, loop-coupled cavities, and harnessing low-loss Bloch waves.

Next, I address the role of nanophotonics in energy-efficient computation, and describe integration of nanophotonics in a state-of-the-art, commercial bulk-silicon CMOS process (65nm node and below) opening the way to large-scale mainstream fabrication of electronic-photonic circuits, and allowing for the first time their full integration in processes compatible with state-of-the-art microprocessors.

Finally, I will introduce a new class of nanophotonic circuits based on forces generated by light on the nano scale and movable nanomechanical parts, which promise ground-breaking new possibilities in terms of functionality. The prospect is of light-powered nanomachines and nano- optomechanical self-adaptive photonic circuits with intrinsic feedback control. I will describe how this new class of devices facilitates resonantly tailored optomechanical potentials, enabling picometer- precision positional control of nanomechanical structures and all-optically self-aligning microcavities that track the wavelength of an incident laser with no external control. These concepts lay the foundation for a fundamentally new class of nanophotonic devices with unique capabilities, scalability advantages, and numerous new applications.


Seminar, March 30, 2009, 10:00. Seminar Room

Hosted by Prof. Lluis Torner