High speed optical modulator enhanced by ‘slow light’ propagation

CEA-Leti is coordinator of the European HELIOS project to accelerate commercialisation of silicon photonics. In an effort to push forward this state of the art technique, an ultra high speed optical modulator enhanced via 'slow light' propagation has now been demonstrated. Slow light propagation is referred to when light travels significantly slower in a modulator than it does through air or in a vacuum. The properties of slow light propagation in a nanostructured 1D periodic waveguide, together with a high speed semiconductor pn diode were exploited to demonstrate a 500µm long silicon electro-optical modulator device, exhibiting modulation rate capabilities reaching 40Gbit/s. Using a dual drive modulation scheme would enable the integration of the developed optical modulator with electronic BiCMOS logic circuitry. According to CEA-Leti, these results are a major breakthrough in the field and offer an opportunity to bridge the mismatch in size and power requirements between advanced cmos electronics and current silicon optical modulators. The 325µ² device, built in a cmos compatible process by CEA-Leti is the result of a collaboration between the Silicon Photonics Group at the Advanced Technology Institute, University of Surrey (UK) and the Valencia Nanophotonics Technology Center at Universitat Politecnica de Valencia (Spain). HELIOS partners have unveiled these results in Optics Express, Vol. 19, Issue 21 and during the 8th International Conference on Group IV Photonics in London (UK) on September 14th-16th 2011, at the prestigious post-deadline session.