Torsten Ackemann

Learn More
The dynamics of a broad-area vertical-cavity surface-emitting laser (VCSEL) with frequency-selective feedback supporting bistable spatial solitons is analyzed experimentally and theoretically. Self-pulsing is observed and indicates at least partial mode-locking of several external-cavity modes. It is argued that mode-locking of spatial solitons is an(More)
Today, most peer-to-peer networks are based on the assumption that the participating nodes are cooperative. This works if the nodes are indifferent or ignorant about the resources they offer, but limits the usability of peer-to-peer networks to very few scenarios. It specifically excludes their usage in any non-cooperative peer-to-peer environment, be it(More)
In recent times, the growth in the number of subscribers of peer to peer networks has been phenomenal. Anonymity being a character of such networks also gave rise to the number of free-riders and malicious behaviors. Though free riders consume network bandwidth and decrease the network performance by displaying selfish behavior, they are not a serious(More)
To my parents and my brother for their love, continued support, and encouragement To my aunt and my cousins for not treating me as a relative but as a family member To my grandfather and uncle Dung as the last kiss Acknowledgments First and foremost, I thank my family and my friends for their continued support, encouragement, and understanding that have(More)
We analyze the strength of the nonlinear refractive index change associated with the saturation of the ground state absorption or gain of self-assembled quantum dot samples under cw optical injection. The model is based on a two-level framework but takes into account the strong coupling of quantum dots to the wetting layer by thermal excitations and Auger(More)
(2012) Adler synchronization of spatial laser solitons pinned by defects. Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners.(More)
  • 1