A Simulation Method to Measure the Tax Burden on Highly Skilled Manpower

A model is presented for simulating the tax burden on highly skilled manpower. The effective average tax rate, defined as the relative wedge between total remuneration and disposable income, is computed. Income and payroll taxes and social security contributions not yielding an equivalent benefit are taken into account. The compensation package consists of cash payments and old-age provision. To integrate retirement benefits and their tax treatment, an inter-temporal approach is used. The results indicate that Germany and France have higher tax burdens than the UK and the USA, that Germany grants the strongest tax relief for families, and that occupational pension plans are favourable in all countries. --personal income tax,highly skilled employees,effective tax burden,pensions

A Simulation Method to Measure the Tax Burden on Highly Skilled Manpower

A model is presented for simulating the tax burden on highly skilled manpower. The effective average tax rate, defined as the relative wedge between total remuneration and disposable income, is computed. Income and payroll taxes and social security contributions not yielding an equivalent benefit are taken into account. The compensation package consists of cash payments and old-age provision. To integrate retirement benefits and their tax treatment, an inter-temporal approach is used. The results indicate that Germany and France have higher tax burdens than the UK and the USA, that Germany grants the strongest tax relief for families, and that occupational pension plans are favourable in all countries

The Effective Tax Burden of Companies and on Highly Skilled Manpower: Tax Policy Strategies in a Globalized Economy

Company taxes and taxes on highly skilled labour both influence the attractiveness of a particular region as a location for investment. We measure the effective tax burden on capital investment and on highly qualified labour in 33 locations across Europe and the United States. We then correlate both types of tax burden in order to study the different tax policy strategies applied in different countries. We identify three causes for different strategies: political institutions, preferences for redistribution and equality, and the position in globalisation and growth. Small countries, high growth rates, and federal structure with high tax autonomy stand for countries with lower tax burdens, especially on companies. Large countries, representative democracies with coalitions, and a high preference for redistribution are likely to induce higher tax burdens. --effective tax burden,tax policy,company taxation,personal income tax

Optimising Four-Wave Mixing in Ultralong SOAs

Abstract-The numerical modelling of four-wave mixing in ultralong semiconductor optical amplifiers (UL-SOAs) is discussed. Inside the UL-SOA, complex wave mixing interactions take place so that time-domain modelling is an important requirement for the simulation model. We validate our simulations by comparison with measurements and show that the confinement factor is a crucial parameter for the device optimisation with regard to the generation of broad FWM combs

Numerical Assessment and Optimization of Discrete-Variable Time-Frequency Quantum Key Distribution

The discrete variables (DV) time-frequency (TF) quantum key distribution (QKD) protocol is a BB84 like protocol, which utilizes time and frequency as complementary bases. As orthogonal modulations, pulse position modulation (PPM) and frequency shift keying (FSK) are capable of transmitting several bits per symbol, i.e. per photon. However, unlike traditional binary polarization shift keying, PPM and FSK do not allow perfectly complementary bases. So information is not completely deleted when the wrong-basis filters are applied. Since a general security proof does not yet exist, we numerically assess DV-TF-QKD. We show that the secret key rate increases with a higher number of symbols per basis. Further we identify the optimal pulse relations in the two bases in terms of key rate and resistance against eavesdropping attacks.Comment: 9 Pages, 4 Figure

Maximal parabolic regularity for divergence operators including mixed boundary conditions

We show that elliptic second order operators $A$ of divergence type fulfill maximal parabolic regularity on distribution spaces, even if the underlying domain is highly non-smooth, the coefficients of $A$ are discontinuous and $A$ is complemented with mixed boundary conditions. Applications to quasilinear parabolic equations with non-smooth data are presented.Comment: 39 pages, 4 postscript figure

Parametrische Verstärkung und Wellenlängenkonversion von phasenmodulierten Signalen

In dieser Arbeit werden Konzepte zur parametrischen Verstärkung und zur Wellenlängenumsetzung theoretisch untersucht, die auf Vierwellenmischung in Materialien mit einer Nichtlinearität dritter Ordnung beruhen. Diese beiden Prozesse könnten eine Reihe von Anwendungen in zukünftigen hoch-kapazitiven faseroptischen Übertragungssystemen finden. Dazu gehört rauscharme Verstärkung mit variablem Gewinnspektrum und beliebigen Mittenwellenlängen, die Kompensation von Nichtlinearitäten in der Faserübertragung durch Phasenkonjugation und die Blockierungsauflösung in Netzknoten durch Wellenlängenumsetzung. Neben der Flexibilität ist vor allem die erwartete Unabhängigkeit vom Modulationsformat und Datenrate ein entscheidender Vorteil für diese Komponenten. Allerdings wurde in bisherigen Arbeiten vor allem die Verarbeitung von amplitudenmodulierten Signalen untersucht, während Phasenmodulationsformate im Bereich der Übertragung schon weiträumig eingesetzt werden. Da eine detaillierte Untersuchung noch aussteht, wird der Fokus der Arbeit auf Aspekte bezüglich der Verarbeitung von digital phasenmodulierten (PSK-) Formaten gelegt. Verschiedene Formate für die direkte (differentielle 2- und 4-PSK) und für die kohärente Detektion (2-PSK, 4-PSK, 8-PSK) werden berücksichtigt, ebenso wie die 16-Quadraturamplitudenmodulation (16-QAM), die sowohl eine Amplituden- als auch eine Phasenmodulation enthält. Während eine große Anzahl von geeigneten nichtlinearen Materialien zur Verfügung steht, werden in der Arbeit nur zwei der vielversprechensten Komponenten, nämlich die hoch-nichtlineare Faser (HNLF) und der Halbleiterlaserverstärker (SOA), mit Hilfe von analytischen und numerischen Rechnungen untersucht. Die zugrundeliegenden Modelle werden detailliert präsentiert. Die Analyse zeigt, dass die parametrischen Komponenten verschiedene Arten von Phasenstörungen hervorrufen, die die PSK-Formate stören und de facto die Formattransparenz einschränken. Ein großer Teil der Arbeit ist der Auswertung des Einflusses auf die verschiedenen Modulationsformate bezüglich der Bitfehlerrate gewidmet. Im Allgemeinen steigt die Empfindlichkeit der PSK-Formate gegenüber den Phasenstörungen mit der Anzahl der Konstellationspunkte an. Auf Grundlage der vorangegangenen Analysen werden im weiteren Verlauf der Arbeit Möglichkeiten diskutiert, wie man die Phasenstörungen kompensieren bzw. vermeiden kann. Generell steht hier die Qualität des Pumplasers im Vordergrund. Falls Hochleistungslaser mit sehr kleinem Amplituden- und Phasenrauschen zur Verfügung stehen, können vernachlässigbare Phasenstörungen und eine damit verbundene fast ideale Formattransparenz in den HNLF-Komponenten erzielt werden. Demgegenüber ist die Optimierung der SOA-Komponenten schwieriger wegen der Sättigungseffekte und der inhärenten Erzeugung von Rauschen.In this thesis, parametric amplification and wavelength conversion based on four-wave mixing in materials with third-order nonlinearity are theoretically investigated. These processes may find a variety of applications in future high-capacity fiber-optic transmission systems including low-noise amplification with variable gain spectrum and arbitrary center wavelength, nonlinearity compensation during transmission through phase conjugation and contention resolution in network nodes through wavelength conversion. Beside their flexibility, one of the expected key advantages for such devices is the possibility for modulation format and bit rate independent operation enabling transparent networking. However, while phase-modulation formats are widespread used in the current transmission systems, most of the previous publications on parametric processes considered only amplitude-modulation formats like on-off keying. Since a detailed investigation is still pending, the focus of the work is put on aspects regarding the processing of phase-shift keying (PSK) formats. Different direct (differential 2- and 4-PSK) and coherent detection formats (2-PSK, 4-PSK, 8-PSK) as well as 16-quadrature amplitude modulation (16-QAM) as a format carrying both amplitude and phase modulation are considered. While various nonlinear materials are available, the thesis is restricted to two of the most promising devices, namely the highly nonlinear fiber (HNLF) and the semiconductor optical amplifier (SOA). They are examined using analytical and numerical calculations with models that are presented in detail within the thesis. The analysis shows that both parametric devices introduce different types of phase distortions that impair phase-shift keying formats and de facto undermine the modulation format transparency. A main part of the thesis is dedicated to the evaluation of their impact on the considered modulation formats in terms of the bit-error rate. As a general trend, the sensitivity of the phase-shift keying formats to the phase distortions increases with the number of constellation points. Based on the preceding analysis, possibilities are evaluated for the mitigation or the prevention of the phase distortions depending on their deterministic or stochastic nature. Generally, the pump laser quality is one major issue. If high-power lasers with very low amplitude and phase noise can be used, low phase distortions and nearly ideal format transparency can be recovered for HNLF-based devices. By contrast, the optimization of SOA-based devices is more difficult due to limits set by saturation effects and the inherent noise generation