The data represents how many vehicles passed by traffic counting stations on three streets. Matlab integrates numerical analysis, matrix computation, signal processing, and graphics in an easytouse environment. The stationary point source gaussian dispersion model rio akasaka 09 engineering 66 the gaussian dispersion model serves as an excellent approximation to point source emission scenarios, such as coal plants with smokestacks. The equation, which describes the effect of gvd on optical pulse propagation neglecting the losses and nonlinearities, is 1. The range range is the difference between the maximum and minimum values in the data, and is strongly influenced by the presence of an outlier. It is relevant for many applications of fiber optics. It can be run both under interactive sessions and as a batch job. We present a graphical user interface gui matlab package called gspecdisp, which is dedicated to phasevelocitydispersion measurements from noise correlations. Rayleigh wave dispersion curve inversion via genetic.
It is shown that at least seventeen rings of arrays of air holes are required in the cladding region to reduce the leakage losses to a level of 0. This is analogous to the electromagnetic dispersion relation 9. Diseca a matlab code for dispersive waveform calculations article in computers and geotechnics 384. The matlab code used to generate these interference patterns is. Intermodal dispersion also called modal dispersion is the phenomenon that the group velocity of light propagating in a multimode fiber or other waveguide depends not only on the optical frequency chromatic dispersion but also on the propagation mode involved. The entire book is freely available in pdf 2up format, and in pdf 1up format. Both the mean absolute deviation mad and the standard deviation std are sensitive to outliers. For numerical evaluation using matlab, it proves convenient to leave. In figure 2, an illustrative example of a s0mode wavepacket at 150 khz is shown. Dispersion analysis of a negative group velocity medium with. Matlab simulink simulation platform for photonic transmission. We want you to see how matlab can be used in the solution of engineering problems. Effect of group velocity dispersion gvd with and without initial gaussian chirp in enhanced large effective area fiber eleaf bhupeshwaran mani, chitra k, sivasubramanian a abstractin this work, the effect and mechanism of group velocity dispersion gvd in enhanced large effective area fiber eleaf is studied.
Using dispersion curves to analyze fluidfilled pipes. Chromatic dispersion is the phenomenon that the phase velocity and the group velocity of light propagating in a fiber depend on the optical frequency. Group delay ripple, produced due to the high deviation of frequency from the mean dispersion slope, is one of the major performance liming factors of this technique. Group velocity, dispersion, and optical pulse compression. I thought maybe the physics community could shed some insight on the issue. Pulse propagation in dispersive media rutgers university. University of pittsburgh, 2004 in wave propagation, the phenomenon of dispersion, whereby di. Multiphase particle tracking by dpmansys fluent youtube. Based on this structural model, a 1d velocity model containing p and s wave velocity distribution with depth was designed. How you can do this in the comsol desktop is described in chapter calling matlab function. Inversion of the experimental dispersion curves is generally an indispensable. The language of technical computing stanford university. Anomalous dispersion, lefthanded media, negative group velocity, gaussian pulse, and matlab.
Surface wave analysis and its application to the calculation. During guided wave propagation, waves experience dispersion that distorts the wave. If p is the pulse length, gvm 1v g 0 2 1v g 0 v g is the group velocity at wavelength, and 0 is the fundamental wavelength, this condition is. The spatial variation is described by a quantity representing phase change per unit distance and is equal to.
Using surface waves, we can estimate an swave velocity model to address the swave receiver statics of converted waves. For modes with l 0 black curves, the group velocity can approach that of the cladding. Homework equations i have been calculating the velocity using this equation. Gspecdisp is an opensource package designed to facilitate and increase the speed of phase velocity measurements. This paper thus describes the modeling techniques for advanced photonic transmission systems and simulink is proven to be very effective platform for development of photonic communications systems due its. Matlab simulink has become the universal mathematical and modeling tools in most universities and research laboratories around the world. In this tutorial, we provide a basic example of goal attainment optimizations. The group velocity is the velocity at which the envelope energy of the wave propagates through the medium. Near a mode cutoff, the group index often drops, i. Dispersion characterization techniques for optical. Computation of partial derivatives of rayleighwave phase. This software allows users to obtain the theoretical solution for dispersion curve, tuning curve, frequency components for.
Diseca a matlab code for dispersive waveform calculations. As we mentioned earlier, the following tutorial lessons are designed to get you started quickly in matlab. Matlab tutorial 2 lecture learning objectives describe the matlab desktop. The interquartile range iqr is the difference between the 75th and 25th percentile of the sample data, and is robust to outliers. Hi, ive created a gaussian pulse and want to apply the group velocity dispersion to it. Cst microwave studio 8 mtalab code for plotting the dispersion diagram for publishing all of your plot result, especially in ieee publications, we should import our data into matlab environment, as a perfect engineering tool to sketch various plots in a unique plot in a high resolution view.
The script uses the phaseshift dispersion imaging scheme of park et al. For example, it has a strong influence on the propagation of telecom signals in optical fiber communications and on the propagation of ultrashort pulses. Implementation and application of dispersionbased waveguide. Matlab also features a family of applicationspecific solutions. This tutorial the purposes of this tutorial is to help you get started with matlab. Dispersion analysis of optical fiber using matlab raviraj prakash nagarkar abstract optical fiber is a dielectric waveguide, cylindrical in shape. Rp photonics encyclopedia tutorial passive fiber optics.
Adaptive equalization for dispersion mitigation in multi. The lessons are intended to make you familiar with the basics of matlab. We developed a matlab package, noisy dispersion curve picking ndcp, which allows full control over several parameters to properly identify group velocity dispersion curves using two types of datasets. Dispersion pl 2pl 3pl 4pl 2w0 w k slope wk phase velocity figure 3 there are various things to note about this. An errata file updated may 15, 2020 is also available here. We can finally look at the group velocity dispersion.
A more modern example of the phenomenon of dispersion is the affect it has on. Characterisationandextractionofarayleighwave quaternionsvd. The simulator is used mainly for investigation of performance of advanced. Effects of group velocity dispersion gvd on gaussian. Two types of phasevelocity dispersion measurements can be carried out. The third term represents higherorder dispersion effects group velocity dispersion, thirdorder dispersion, etc. Inversion of observed surface wave dispersion curves is used in many fields, from seismology to earthquake and environmental engineering. It confines electromagnetic energy in the form of light within its surface and guides light by multiple internal reflections, provided the angle of incidence onto the core cladding interface is. For partial derivatives of rayleighwave group velocity, a hemianalytical. This software allows users to obtain the theoretical solution for dispersion curve, tuning curve, frequency components for s0 and a0 wave modes, and the plate transfer function. The group velocity dispersion still limits the bit ratedistance productblby broadening optical pulses beyond their allocated bit slot. This example shows how to use matlab data statistics to calculate and plot statistics for a 24by3 matrix, called count. Hence, it clearly shows the frequencydependence of the group velocity.
Scott hinton utah state university beng 55006500 lesson. Rayleigh wave dispersion curve inversion via genetic algorithms and marginal posterior probability density estimation giancarlo dal moro. Using the vdisp program, for this velocity model, we computed the rayleigh wave phase velocity dispersion curves of the fundamental and the. The groupvelocity dispersion still limits the bit ratedistance productblby broadening optical pulses beyond their allocated bit slot. Necessarily, it goes into some detail about concepts such as group velocity, phase accumulation, and so on.
Even though 1 does not provide a complete physical description of a system, it is the basis for modeling optical. Gspecdisp is an opensource package designed to facilitate and increase the speed of phasevelocity measurements. Will read a couple of sections and then go to a computer to experiment with matlab. The data statistics dialog box helps you calculate and plot descriptive statistics with the data. Shear wave velocity is estimated from the inversion of either phase or group velocity. The wavelength dependence and the structural dependence of leakage loss and group velocity dispersion gvd in aircore photonic bandgap fibers pbgfs are numerically investigated by using a fullvector finite element method. Rayleighwave propagation in a layered, elastic earth model is frequencydependent dispersive and also function of the swave velocity, the pwave velocity, the density and the thickness of the layers. About the tutorial matlab is a programming language developed by mathworks. This is related to the weaker mode confinement in that regime. Many thanks to all who have sent me errata and, especially.
This means that different frequency components of an optical pulse travel at different velocities, hence leading to the spreading of the pulse or known as the dispersion. This is the group velocity and is which can be found if you have giving 7 v. Matlab i about the tutorial matlab is a programming language developed by mathworks. Thermal noise parameter of pin will be extracted to get a receiver sensitivity of 17 dbm. Lecture notes essentials of geophysics earth, atmospheric. Effect of group velocity dispersion gvd with and without. Im looking for it to be similar to he image attached, where the top is the original pulse, the middle is positive dispersion and the bottom is negative dispersion, as im trying to understand how they did this. Individual chapters are available below in pdf in 2up format. Surfacewave twostation dispersion analysis gui software in matlab whats the tomography method. This tutorial gives you aggressively a gentle introduction of matlab programming language. Applied sciences free fulltext a matlab package for. Group velocity the phase velocity of a wave is and comes from the change in the position of the wavefronts as a function of time the waveform moves at a rate that depends on the relative position of the component wavefronts as a function of time. A bandwidthlimited pulse can only be kept together if the dispersion of the medium the wave is travelling through is zero.
I need to implement a numerical scheme for the solution of the first order wave propagation equation with chromatic dispersion included. It started out as a matrix programming language where linear algebra programming was simple. For example, when an ultrashort pulse passes through a block of glass, the glass medium broadens the pulse due to group. In this example we will use the optimization tool in the context of parameter extraction. Nov 08, 2017 using dispersion curves to analyze fluidfilled pipes. We discuss group velocity dispersion, pulse spreading, chirping, and dispersion. On the contrary, dispersion compensation modules dcms 10 using fbg is not suitable for the broadband transmission due to narrow operating wavelength range 11. One wavelength corresponds to an xdependent phase difference of 2 k. To demonstrate the influence of the group gvd velocity dispersion on pulse propagation in optical fibers in linear regime. Automated surface wave phase velocity measuring system, measuring twostation phase delay and then 2d phase velocity maps at each period using eikonal and helmhotza tomography. Typically, lambwave patterns can be observed when there is a highvelocity stiff layer at the top of a nearsurface section. Creating a phasevelocity diagram with matlab physics forums. Masw dispersion curve file exchange matlab central.
We present a graphical user interface gui matlab package called gspecdisp, which is dedicated to phase velocity dispersion measurements from noise correlations. Numerical solution of the propagationdispersion equation. Leverage matlab functionality for program flow use the api syntax together with matlab functionality to control the flow of your programs. I have asked this question on computational science and also on mathoverflow, but no satisfactory answers so far. Tutorial matlab optimization toolbox introduction matlab is a technical computing environment for high performance numeric computation and visualization. Based on the analysis of profile measurements, using body and surface waves, a 1d structural model of the medium was determined. Rp photonics encyclopedia intermodal dispersion, modal.
Stateflow charts receive inputs from simulink and provide outputs signals, events simulation advances with time hybrid state machine model that combines the semantics of mealy and moore charts with the extended stateflow chart semantics. Optimization of the splitstep fourier method in modeling. In such instances, some parts of the dispersion curves may exhibit features that resemble lambwave plate wave patterns and not rayleigh wave, free rayleigh waves can only. Thus group velocity, can never be more than the speed of light in a vacuum, c. By local moments we mean, for example, the spread standard deviation of the. For example, if the dispersion length is much less than the nonlinear length. Pulse propagation dramatic improvements in the development of. This zip file contains a sample shotgather data set and a script to calculate the dispersion image of the data. This is essentially the frequency derivative of the.
We urge you to complete the exercises given at the end of each lesson. How to use dispersion curves to analyze fluidfilled pipes. Osa leakage loss and group velocity dispersion in air. It is the velocity at which the energy or information in the waveform moves. But this type of fiber has several drawbacks, such as higher polarization mode dispersion than itu g. For nondispersive signals, the two velocities match and the phase shift is null. Group velocity and phase velocity san jose state university.
367 1575 469 1079 334 109 1442 297 37 435 554 490 774 1006 1315 1603 1051 75 1097 264 1601 778 470 643 1366 378 389 62 746