Jens Kissing

Coarse WDM/CDM/TDM concept for optical packet transmission in metropolitan and access networks supporting 400 channels at 2.5 Gb/s peak rate

To improve the networking flexibility in the metropolitan and access area, the granularity in the optical domain has to be increased above that in the core network requiring more channels at lower bit rates. Pure dense wavelength division multiplexing (DWDM) as it is applied in the core does not seem to meet this requirement at affordable cost. We propose and analyze a network based on hybrid optical multiplexing techniques including wavelength, code, and time division multiplexing. Applied to optical packet transmission this approach enables several 100 all-optical channel between end users and headend with average bit rates up to 100 Mb/s per channel while keeping the installation and maintenance cost at a minimum.

Analytical probability density function for the Q factor due to PMD and noise

The statistics of the signal quality due to first-order polarization mode dispersion (PMD) in uncompensated systems is analyzed. First, the probability density function (pdf) of the eye-opening penalty (EOP) due to first-order PMD is presented. Based on an analytical relation between Q factor and EOP, the pdf of the Q factor is determined. By integration of this pdf, the outage probability (OP) is derived. The OP is determined by including the optical signal-to-noise ratio (OSNR) and the differential group delay (DGD). Finally, the OSNR penalty for the required OP and a certain average DGD is derived, which is an important result for system designers. All analytical results are verified by simulations.

Performance evaluation of a CDMA system using broadband sources

A rigorous numerical model for the performance evaluation of multiple access systems with broadband sources is presented. The model is applied to analyse a spectrally coded CDMA system using frequency periodic optical filters. Newly obtained results are discussed.

Signal degradation by second-order polarization-mode dispersion and noise

To specify the impact of polarization-mode dispersion (PMD) on optical signal transmission, formulas are derived both for the effective pulse broadening and the eye-opening penalty up to second order. Furthermore, a probability density function of the Q factor is set up due to second-order PMD and amplified spontaneous emission noise. The relations are verified by numerical simulations.

Bidirectional optical code division multiplexed field trial system for the metro and access area

A fully operational bidirectional optical code division multiplexed system has been successfully implemented within the KomNet field trial. 4/spl times/155.52 Mbit/s signals each in up- and downlink are transmitted over a 20 km two fibre feeder. Transmission of the signals over DWDM metro rings is discussed.

Simulation and modeling of photonic WDM systems

A general modeling and simulation strategy suitable for the theoretical analysis of wavelength division multiplexed (WDM) fiber-optical systems is presented. We give a detailed explanation of component models and algorithms of different complexity and accuracy which can be used throughout the simulation. Transmitter chirp and noise, fiber dispersion and nonlinearity, imperfect filter and multiplexer characteristics, amplified spontaneous emission noise of the optical amplifiers, crosstalk in network elements such as optical add/drop multiplexers or optical cross-connects, and the polarization-dependence of the components are taken into account. Methods for a performance evaluation by means of eye patterns, spectral power densities, the optical signal-to- noise ratio, the Q-factor and the bit error rate are also addressed. Based on this work, a complete design environment consisting of a graphical network editor and an independent simulation engine (FOCUSS, Fiber Optic CommUnication System Simulator) has been implemented in C++. Simulation examples are presented here e.g. for wavelength-routed networks.

Analysis of an Improved Split-Step Algorithm for Simulating Optical Transmission Systems

Summary The standard Split-Step algorithm for calculating the signal transmission through optical fibres is significantly accelerated without relevant loss of accuracy by applying IIR filters as well as Fourier transformations for the linear operator. Depending on the system topology, high speed-up factors can be achieved by switching back and forth between time and frequency domain algorithms for the linear operator. Two different IIR filters are applied for calculating linear and parabolic dispersion. The efficiency of this algorithm in combination with an innovative step-size allocation method is evaluated.

A robust and flexible all optical CDMA multichannel transmission system for the access domain

A multichannel optical CDMA system for the access domain, which is fully variable in terms of channel data rate and channel number is presented. Various network functionalities are illustrated, which are completely realized on the optical layer.