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Item type:Publication, Access status: with files , Laser-to-RF phase detection with femtosecond precision for remote reference phase stabilization in particle acceleratorsThe invention of a femtosecond stable Laser-to-RF phase detector allows to measure with femtosecond precision the relative phase between a phase stable optical reference and an RF signal. Thereby one can stabilize RF reference signals in modern FELs on a femtosecond scale. A pulsed optical synchronization system is used to deliver the required optical reference signals. The L2RF phase detector is based on an integrated Mach-Zehnder modulator (MZM) in which the phase error between both signals is encoded in an amplitude modulation of the optical pulse train. Different configurations for different operation scenarios have been evaluated. A full mathematical representation has been derived. The impact of multiple error sources has been investigated. Error sources of the measurement setup have been identified and eliminated. The femtosecond performance has been verified with two different prototypes. The achieved stability of 3.6fs over 12h is currently unmatched.Publicationtype: Doctoral Thesis607 1164 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Charakterisierung integriert-optischer Silizium-Wellenleiter(2013); In this work, measurement techniques for the characterization of integrated optical waveguides based on the SOI-technology are presented. Silicon nanophotonic waveguides are investigated regarding their linear waveguide losses as well as the lifetime of free charge carriers. A novel measurement technique based on optical frequency-domain reflectometry (OFDR) for the evaluation of the longitudinal attenuation profile of silicon waveguides is introduced. The non-reciprocal behaviour of Raman scattering in silicon waveguides is experimentally shown. Furthermore, a technique for the implementation of periodically structured photoresists on silicon substrates based on DUV-lithography with diffraction gratings is demonstrated.Publicationtype: Doctoral Thesis742 1816 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Efficient Raman amplifiers and lasers in optical fibers and silicon waveguides : new concepts(2007); In this thesis, several new concepts for Raman amplifiers and lasers both in optical fibers and silicon waveguides have been developed, modeled and optimized that have the potential of increasing the performance of fiber-optic communication systems. Designs for Raman fiber lasers with improved efficiency, tunability, and output noise are analyzed. On the other hand, fundamental properties and limitations of silicon-based Raman amplifiers and lasers are investigated. Based on a newly developed comprehensive mathematical model of nonlinearly coupled wave propagation in silicon waveguides, new designs with increased efficiency are proposed.Publicationtype: Doctoral Thesis615 1503