Car-oriented mean-field theory for traffic flow models

We present a new analytical description of the cellular automaton model for single-lane traffic. In contrast to previous approaches we do not use the occupation number of sites as dynamical variable but rather the distance between consecutive cars. Therefore certain longer-ranged correlations are taken into account and even a mean-field approach yields non-trivial results. In fact for the model with $v_{max}=1$ the exact solution is reproduced. For $v_{max}=2$ the fundamental diagram shows a good agreement with results from simulations.Comment: LaTex, 10 pages, 2 postscript figure

First 10Gb/s Transmission with radiation-hardened Silicon Photonic Mach-Zehnder Modulators in a Full Transmission System

We present standard and radiation-hardened pn depletion-type Mach-Zehnder modulators (MZM) to be used in high-bandwidth, fully-integrated wavelength division multiplexing (WDM) transmitter designs, aiming to upgrade the optical data transmission of future detector systems. A detailed characterization of the modulators with respect to modulation efficiency and RF response was carried out. Based on this work, a first optical link with a data rate of 11.3 Gb/s was set up

Key building block optimization for high-performance transceivers: Multimode interferometers from conventional to sub-wavelength regime

Multimode interferometers (MMIs) are key components for high-bandwidth transceivers in upgrading the data transmission of future detector systems. We present two conventional highperformance MMIs fabricated on a 250 nm SOI platform with different power splitting ratios which operate as 50%:50% power splitter for Mach-Zehnder modulators and as 86%:14% power splitter for loop control in future transceiver designs, respectively. Besides, we present the novel MMIs based on sub-wavelength gratings. By engineering the refractive index of relevant parts, more compact 50%:50% MMIs and multi-port, low phase error MMIs become feasible