Integrated silicon optical modulators

Optical modulators are central to a large number of applications in photonics particularly in the area of communication as they provide the function of writing electrical data onto an optical carrier. Silicon photonics provides a route to the realisation of low cost photonic integrated circuits through fabrication which is synonymous with CMOS electronic fabrication, i.e., high volume and high yield. The development of high performance optical modulators based on a silicon photonic platform can therefore support a number of low cost applications. Tremendous progress has been made in the realisation of high performance silicon based optical modulators over the last decade. Successful demonstrations have been made of `silicon only' approaches which are based upon the plasma dispersion effect as well as hybrid approaches involving the incorporation of other materials such as III-V compounds, SiGe, graphene, or organic materials. On the component level, a large amount of research is ongoing worldwide to achieve increased levels of performance in different metrics such as speed, power consumption, modulation depth, footprint, wavelength independence, temperature insensitivity and optical loss. Furthermore, other significant research is underway in the area of silicon optical modulators including the use of more complex modulation formats, modulation at non-conventional wavelengths, the integration of the modulator into more complex photonic systems and the integration of high performance drive electronics. At the University of Southampton we are working on a number of projects across these different research focuses. Here we present an overview of our recent progress and results in these areas.