Papers by christos braimiotis
2009 IEEE/LEOS Winter Topicals Meeting Series, 2009
Nonlinear Guided Waves and Their Applications, 2004
The effect of having a fixed differential-group delay term in the coarse-step method results in a... more The effect of having a fixed differential-group delay term in the coarse-step method results in a periodic pattern in the autocorrelation function. We solve this problem by inserting a varying DGD term at each integration step, according to a Gaussian distribution. Simulation results are given to illustrate the phenomenon and provide some evidence,about its statistical nature.
Nonlinear Guided Waves and Their Applications, 2005
Optics Express, 2008
We improve the accuracy of numerical simulations for short fiber optical parametric amplifiers (O... more We improve the accuracy of numerical simulations for short fiber optical parametric amplifiers (OPAs). Instead of using the usual coarse-step method, we adopt a model for birefringence and dispersion which uses finestep variations of the parameters. We also improve the split-step Fourier method by exactly treating the nonlinear ellipse rotation terms. We find that results obtained this way for two-pump OPAs can be significantly different from those obtained by using the usual coarse-step fiber model, and/or neglecting ellipse rotation terms.
IEEE Journal of Quantum Electronics, 2000
We show by means of analytical calculations and numerical simulations that the impact of polariza... more We show by means of analytical calculations and numerical simulations that the impact of polarization-mode dispersion (PMD) on the gain spectrum of fiber optical parametric amplifiers (OPAs) can be reduced by imposing twists along the fiber axis. Alternating twists are used in order to cancel the induced circular birefringence.
IEEE International Conference on Communications, 2013
The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for... more The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for today's data-heavy applications. However, these data-heavy applications require lots of battery power on the user equipment. To extend the user equipment battery lifetime, plus further support various services and large amount of data transmissions, the 3GPP standards for LTE/LTE-Advanced has adopted discontinuous reception (DRX). In this paper, we take an overview of various static/fixed DRX cycles of the LTE/LTE-Advanced power saving mechanisms, by modelling the system with bursty packet data traffic using a semi-Markov process. Based on the analytical model, we will show the trade-off relationship between the power saving and wake-up delay performance. This work will help to select the best parameters when LTE/LTE-Advanced DRX is implemented depending on the protocols and desired outcome of the traffic.
The phenomenon of polarisation mode dispersion in optical fibres is normally modelled using the c... more The phenomenon of polarisation mode dispersion in optical fibres is normally modelled using the coarse-step method. This approach is based on the idea of replacing the continuous random birefringence by a sequence of randomly connected fibres each of which has a constant ...
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Papers by christos braimiotis