![]() ![]() ![]() Tabulated index data are less suitable, since the numerical differentiation is sensitive to noise.įor light propagating in waveguides such as optical fibers, one considers the phase constant β instead of the wavenumber k. The dispersion of various orders for a medium can most conveniently be calculated if the refractive index is specified with a kind of Sellmeier formula. in numerical modeling to work directly with a table of frequency-dependent phase changes. It is therefore often more convenient e.g. Ultimately, the concept of Taylor expansion loses its value in this regime, where many dispersion orders have to be considered. When dealing with very broad optical spectra, one sometimes has to consider dispersion up to the fourth or even fifth and sixth order. Zero group delay dispersion is reached close to 1270 nm.ĭispersion of third and higher order is called higher-order dispersion. Mathematical Description of Chromatic DispersionĪs an example, the group delay dispersion of silica is +36 fs 2/mm at 800 nm, or −22 fs 2/mm at 1500 nm. The attribute “chromatic” is used to distinguish that type of dispersion from other types, which are relevant particularly for optical fibers: intermodal dispersion and polarization mode dispersion.Ĭhromatic dispersion can also occur from geometrical effects, for example see below the section on chromatic dispersion of optical components. That dependency results mostly from the interaction of light with electrons of the medium, and is related to absorption in some spectral regions see the article on Kramers–Kronig relations.Ī quantitative measure is the group velocity dispersion. The chromatic dispersion of an optical material is the phenomenon that the phase velocity and group velocity of light propagating in a transparent medium depend on the optical frequency. #DEFINE CHROMATIC HOW TO#How to cite the article suggest additional literature More specific terms: normal and anomalous dispersion, material dispersion, waveguide dispersion, group delay dispersion, third-order dispersion, principal dispersion Using our ad package, you can display your logo and further below your product description.Īsk RP Photonics for any kind of calculations concerning chromatic dispersion and its effects in various situations.ĭefinition: the frequency dependence of the phase velocity in a transparent medium ![]()
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