Gottfried Lehmann
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Featured researches published by Gottfried Lehmann.
optical fiber communication conference | 2005
J.P. Turkiewicz; E. Tangdiongga; Gottfried Lehmann; Harald Rohde; Wolfgang Schairer; Yu Rong Zhou; Esr Sikora; Andrew Lord; David B. Payne; G.D. Khoe; H. de Waardt
This paper reports a 160-Gb/s OTDM network comprising switching and demultiplexing through field deployed fiber. The 160-Gb/s signal was obtained by time-interleaving 16 channels of a 10-Gb/s signal. The add-drop node was realized by using a gain-transparent operation of a semiconductor optical amplifier (SOA). A subharmonic clock recovery with a prescaled electrooptical phase locked loop employing an electroabsorption modulator was applied. An OTDM receiver employed a four-wave mixing principle in an SOA. The impact of fiber chromatic and polarization-mode dispersion (PMD) is discussed. Switching and demultiplexing performance are shown for a fiber link of 275 and 550 km, respectively. Excellent operation of clock recovery, drop-through-add function, and transmission was achieved.
optical fiber communication conference | 2006
Rainer H. Derksen; Gottfried Lehmann; C.-J. Weiske; Colja Schubert; Reinhold Ludwig; Sebastian Ferber; Carsten Schmidt-Langhorst; Michael Möller; Joachim Lutz
We report an integrated ETDM receiver for 100 Gbit/s, which comprises 1:2-demultiplexing and clock & data recovery on a single chip. The ETDM receiver was tested successfully in a 100 Gbit/s transmission experiment over 480 km dispersion managed fiber.
optical fiber communication conference | 2007
Colja Schubert; Rainer H. Derksen; Michael Möller; Reinhold Ludwig; C.-J. Weiske; Joachim Lutz; Sebastian Ferber; Andreas Kirstädter; Gottfried Lehmann; Carsten Schmidt-Langhorst
Ethernet in backbone networks has the potential to provide high-performance and cost-efficient networking solutions. Driven by the rapid growth of Ethernet traffic, it is likely that, in the transport network, the next step in terms of the data rate will be 100 Gb/s. In this paper, we report on an integrated electrical-time-division-multiplexing (ETDM) receiver for 100/107 Gb/s, which comprises 1 : 2 demultiplexing and clock-and-data recovery on a single chip. The ETDM receiver was tested successfully in 100- and 107-Gb/s transmission experiments over 480-km dispersion-managed fiber
optical fiber communication conference | 2007
Gottfried Lehmann; Rainer H. Derksen; Colja Schubert; Marcus Winter
Solutions to transmit 100 gigabit Ethernet signals (GbE) over hundred or more kilometers are discussed. An overview of experimental ges 100 Gb/s ETDM approaches is given and the suitability of various modulation formats is evaluated.
european conference on optical communication | 2006
Svetoslav Duhovnikov; Dominic A. Schupke; Gottfried Lehmann; Thomas Fischer; Franz Rambach
We propose a fast and simple RWA algorithm with physical constraints which are modeled by linear restrictions based on wavelength groups, length, and hops. Simulation results indicate blocking performance close to unconstrained RWA.
Proceedings of SPIE | 2002
Gottfried Lehmann; E. Meissner
For 10 Gb/s and 40 Gb/s NRZ signals the maximum reach of a WDM transmission system depends on the optimization of the inline dispersion scheme, which is different for both data rates for SPM limited transmission systems. Therefore, a mixture of both data rates in the same fiber may cause an impairment of the system performance. This can be reduced introducing additional pre-compensation. The value for the optimum pre-compensation varies with the inline dispersion scheme and the launch power. A design rule to determine the optimum pre-compensation was derived empirically for SSMF and NZDSF. For fixed inline dispersion compensation on SSMF, the maximum reduction of the system reach without pre-compensation is found to be up to 6 dB, compared to optimized inline dispersion compensation schemes. By applying optimal pre-compensation this impairment can be reduced to less than 1 dB. For NZDSF with pre-compensation the system performance can also be improved significantly. Thus WDM systems using different line rates at the individual wavelengths are possible with only a small penalty.
optical fiber communication conference | 2006
Yu Rong Zhou; Andrew Lord; Stefano Santoni; Dario Setti; Thomas Fischer; Gottfried Lehmann; Henning Bülow; Herbert Haunstein; Alfons Schinabeck
PMD rules are developed from transmission modeling, enabling a fast and accurate estimate of the PMD penalty with and without mitigation, which are well suited for the physical constraint-based routing computation
optical fiber communication conference | 2006
Matthias Schuster; Gottfried Lehmann; Dominic A. Schupke; Svetoslav Duhovnikov; Gernot Göger
In long haul WDM-systems the reach of the individual channels depends on the wavelength. In all optical networks this can be used to avoid regeneration if an appropriate wavelength assignment is applied. Network case studies support the according simulation results.
Proceedings of SPIE | 2005
Gottfried Lehmann; Matthias Schuster; Dominic A. Schupke; Svetoslav Duhovnikov; Gernot Göger
The transmission performance in WDM-systems is different for the individual WDM channels. We investigated systematically this variation and wavelength dependence by using semi-analytical simulations. The benefit of this behavior in transparent optical networks is discussed and demonstrated in network case studies.
Proceedings of SPIE | 2005
Harald Rohde; Gottfried Lehmann; Wolfgang Schairer; Jaroslav P. Turkiewicz; E. Tangdiongga; Huugh de Waardt; G.D. Khoe; Ed S.R. Sikora; Yu Rong Zhou; Andrew Lord; David B. Payne
An overview of a wide choice of current technologies and components suitable for the use of 160 Gbit/s optical time domain multiplexing (OTDM) systems is given. A selection of the presented components were used to implement a 160 Gbit/s network. In a field trial on BT’s network we demonstrated transmission over 550 km and a fully operating OTDM network including a time domain add-drop multiplexer (TD-OADM) at a data rate of 160 Gbit/s at a single wavelength and a tributary data rate of 10 Gbit/s.