C. Glingener

Mixed finite element beam propagation method

An efficient mixed finite element (FE) beam propagation method (BPM) for three-dimensional (3-D) simulations is developed for integrated optic devices. Wide angle propagation is allowed by applying Pade approximants to the finite element operator. Mixed finite elements prevent spurious modes and accurately model waveguide corners allowing the adequate description of polarization effects. Furthermore, the finite element matrices are Hermitian leading to a unitary propagation scheme if lossless waveguides surrounded by metallic walls are assumed. In contrast to finite difference schemes energy conservation holds explicitly.

Novel generalized finite-difference beam propagation method

An efficient finite-difference beam propagation method is developed for integrated optic devices. It is based on a numerically efficient and strictly unitary rational approximation of the Helmholtz propagation operator, and is evaluated recursively without matrix inversions. This method satisfies energy conservation in lossless waveguides, is unconditionally stable, and an optimum propagation step can be assessed analytically. Photonic devices with step-index distributions, small layer thicknesses, and arbitrarily large index differences can be simulated. The accuracy and applicability of this new technique is demonstrated for several 2D and 3D examples. Furthermore, the algorithm can easily be implemented even for 3D problems. >

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.

Germany-wide DWDM field trial: transparent connection of a long haul link and a multiclient metro network

We report on error-free multiclient transmission over a Germany-wide all-optical, configurable DWDM system. The performance of the transparent connection of a metropolitan area network and a bi-directional long haul system is investigated under real-world conditions. We report on the topology of SIEMENS part of the Germany-wide field trial KOMNET and results of transparent interconnections between different optical domains.

Modeling of optical waveguide modulators on III-V semiconductors

Efficient two-dimensional algorithms for the analysis of optical waveguide modulators are developed. The basic semiconductor equations are solved numerically taking into account carrier degeneracy, heterojunctions, and the nonparabolic band structure of the GaAs- and InP-based III-V compounds. An analytical, semiempirical model is utilized for the fundamental dielectric function. The variation of the dielectric function due to field related and carrier related phenomena, i.e., linear electrooptic-, electrorefractive- and plasma effects, bandfilling and bandgap shrinkage, are considered. The induced anisotropy and losses are described by a dielectric tensor. Therefore, the vectorial wave equation is solved using a perturbation method. The theoretical results are in excellent agreement with experimental data. >