Electrooptic Modulation in Silicon Photonic Structures
Introduction Hybrid SOI/polymer nanophotonics research at the Institute of Optical and Electronic Materials aims to combine the advantageous optical properties of silicon and EO-active polymers. Silicon with its high refractive index acts as passive waveguide core and enables high scalability to very small device footprint sizes. Furthermore, monolithic integration with electronic circuits and use of mature CMOS technology is possible. Polymers allow to be designed in their molecular structure to have specific optical properties. Today's polymers possess Pockels coefficients of up to 300 pm/V and allow very fast low voltage tuning of the refractive index. The combination of both materials results in simple SOI photonic devices within a polymer cladding that transfers its refractive index shifts into effective refractive index shifts of the guided mode. Goals The main goals of our research are the optimization of the waveguide geometry for the best translation of the cladding's refractive index change into the guided mode's effective index change (e.g. slot waveguides) and the modification of relatively simple device layouts for low loss electrical contacting of the optical waveguides (e.g. segmented waveguides). In particular we are evaluating the possibility to enhance the sensitivity of the propagation constant to EO induced refractive index changes by using high Q photonic crystal cavities and ring resonators. We showed that photonic crystals can be combined with slotted wave guides to obtain both optic confinement and electric contacts as well as improved EO sensitivity. Following this approach we were able to demonstrate EO modulation up to 40 GHz
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Introduction Hybrid SOI/polymer nanophotonics research at the Institute of Optical and Electronic Materials aims to combine the advantageous optical properties of silicon and EO-active polymers. Silicon with its high refractive index acts as passive waveguide core and enables high scalability to very small device footprint sizes. Furthermore, monolithic integration with electronic circuits and use of mature CMOS technology is possible. Polymers allow to be designed in their molecular structure to have specific optical properties. Today's polymers possess Pockels coefficients of up to 300 pm/V and allow very fast low voltage tuning of the refractive index. The combination of both materials results in simple SOI photonic devices within a polymer cladding that transfers its refractive index shifts into effective refractive index shifts of the guided mode. Goals The main goals of our research are the optimization of the waveguide geometry for the best translation of the cladding's refractive index change into the guided mode's effective index change (e.g. slot waveguides) and the modification of relatively simple device layouts for low loss electrical contacting of the optical waveguides (e.g. segmented waveguides). In particular we are evaluating the possibility to enhance the sensitivity of the propagation constant to EO induced refractive index changes by using high Q photonic crystal cavities and ring resonators. We showed that photonic crystals can be combined with slotted wave guides to obtain both optic confinement and electric contacts as well as improved EO sensitivity. Following this approach we were able to demonstrate EO modulation up to 40 GHz
Wissenschaftliche Kontakte und Kooperationen
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