Silicon Photonics for telecommunications
Silicon photonics deals with the study of photonic phenomena and devices that are based on silicon as an optical medium, with the final goal of integrating photonic and electronic functionalities in the same silicon chip. The starting system is Silicon-On-Insulator (SOI), which is subject to fabrication processes that rely on CMOS technology. Optical propagation takes place at the wavelength of optical fiber communications, i.e. around 1.54 micron, where silicon is transparent and Si-based waveguides with very low losses can be realized. Most promising applications in the area of optical communication range from transnational to local-area networks, as well as computer interconnections in data centers. Several large industries like IBM, Intel, ST Microelectronics as well as numerous laboratories worldwide are developing wide-range research programs in this area, which has bright potential for the development of novel solutions and applications for the global market.
Our research in silicon photonics for telecommunications is focused on the problem of coupling the optical signal from a single-mode optical fiber into an integrated silicon chip. This is a crucial issue for connecting the long-distance telecom network to optical silicon-based devices. Specifically, we aim at designing and realizing a two-dimensional grating coupler which couples the unpolarized light signal from an optical fiber into two silicon waveguides on SOI, with the maximum coupling efficiency and with the minimum dependence on the polarization status of light in the fiber. The activity falls within EU FP7 project "FABULOUS", which deals with a new generation of Passive Optical Networks. Grating couplers are designed in Pavia (Physics Department), fabricated at CEA-LETI (Grenoble), tested in Pavia (Engineering Department), and finally packaged at Tyndall Institute (Cork). Other devices that are designed and realized within the project include passive components (tapered waveguides, Mach-Zehnder interferometers) and active ones (SOA, modulators).
L.C. Andreani, A. Bozzola, L. Carroll, D. Gerace (Department of Physics), I. Cristiani, G. Giuliani, C. La Cava, P. Minzioni (Department of Electrical, Computer, and Biomedical Engineering)
Optocom Group, Politecnico di Torino, Italy (R. Gaudino, S. Abrate)
Photonics Packaging, Tyndall National Institute, Cork, Ireland (P. O'Brien)
CEA-LETI, Grenoble, France
ST Microelectronics, Cornaredo, Milano and Studio di Microelettronica, Pavia, Italy (A. Fincato)
EU FP7 Specific Targeted REsearch Project "FABULOUS: FDMA Access By Using Low-cost Optical network Units in Silicon photonics" 2012-2015. Responsibles for Pavia unit: I. Cristiani, L.C. Andreani. Status: Running
Broad parameter optimization of polarization-diversity 2D grating couplers for silicon photonics,
Lee Carroll, Dario Gerace, Ilaria Cristiani, Sylvie Menezo, and Lucio C. Andreani