Nonlinear integrated photonics on CMOS compatible platforms
Main list: Physics and Astronomy Colloquia
The exponential growth in the amounts of data exchanged through the Internet already poses some challenges regarding the energy consumption, size, cost and speed of the associated optoelectronic equipment to route and transfer the information across the network. This calls for the development of new technologies that are intrinsically fast and more energy efficient. A possible solution is to route and manage these high speed data directly in the optical domain, within devices that are meant to be compact and integrated onto a single platform, for instance by exploiting the optical nonlinear properties of the underlying material. In this context, integrated nonlinear optics is advantageous, provided that the material platform yields a high nonlinear response and is CMOS compatible to leverage the huge investment of the microelectronics industry. While SOI has now become extremely mature for passively transferring light information on a chip at Telecom wavelengths with very low loss, its nonlinear response is compromised by a high nonlinear absorption at telecom wavelengths, which limits certain applications (parametric amplification for instance) and tends to restrict the device operation speed (via the generation of free carriers, for instance). I will present here the use of alternative material platforms such as hydrogenated amorphous silicon, in collaboration with CEA-Leti, which provides a better nonlinear performance than crystalline silicon, while maintaining the compatibility with CMOS fabrication technologies. We will discuss the potentialities offered by combining this material with structures providing a tight confinement of light (like photonic crystals) and dispersion engineering techniques to move beyond silicon photonics and perform all-optical signal processing on-chip at Telecom wavelengths.
Beside telecommunication applications, the mid-IR range (between 2 and 5um) represents a spectral window of huge interest for biophotonic and sensing applications, due to the strong signature of biochemical compounds in this range. The associated technology is yet extremely power hungry and very expensive. Here again, the development of integrated optics and the migration of some concepts developed in the near-IR to the mid-IR are required to lead to the widespread use of this technology. One key challenge is the realization of integrated broadband light sources on chip covering a wide spectral window within a single device. We will discuss here the potential of the SiGe alloys, which provide a CMOS compatible platform, with linear and nonlinear properties that have been so far unexplored in the mid-IR
Lecture Theatre C, Physics, University of St. Andrews, St. Andrews, Fife, Scotland
February 12, 2016
From: 10h00 To: 11h00