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Area Optical fibre communication / General concepts

IEV ref731-01-14

en
degree of coherence
a measure of the extent to which radiation can be considered to be coherent

Note 1 – The magnitude of the degree of coherence is equal to the visibility, V, of the fringes of a 2-beam interference experiment:

V= S max S min S max + S min MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiaabAfacaqG9aWaaSaaaeaacaWGtbWaaSbaaSqaaiaab2gacaqGHbGaaeiEaaqabaGccqGHsislcaWGtbWaaSbaaSqaaiaab2gacaqGPbGaaeOBaaqabaaakeaacaWGtbWaaSbaaSqaaiaab2gacaqGHbGaaeiEaaqabaGccqGHRaWkcaWGtbWaaSbaaSqaaiaab2gacaqGPbGaaeOBaaqabaaaaaaa@482B@

where Smax is the irradiance at a maximum of the interference pattern, and Smin is the irradiance at a minimum.

Note 2 – Optical radiation is considered highly coherent when the degree of coherence exceeds 0.88, partially coherent for values less than 0.88 and incoherent for values significantly less than 0.88.


fr
degré de cohérence, m
quantité qui exprime la plus ou moins grande cohérence d'un rayonnement

Note 1 – Le degré de cohérence entre deux ondes est égal à la visibilité V des franges dans une interférence entre ces ondes:

V= S max S min S max + S min MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiaabAfacaqG9aWaaSaaaeaacaWGtbWaaSbaaSqaaiaab2gacaqGHbGaaeiEaaqabaGccqGHsislcaWGtbWaaSbaaSqaaiaab2gacaqGPbGaaeOBaaqabaaakeaacaWGtbWaaSbaaSqaaiaab2gacaqGHbGaaeiEaaqabaGccqGHRaWkcaWGtbWaaSbaaSqaaiaab2gacaqGPbGaaeOBaaqabaaaaaaa@482B@

Smax et Smin sont proportionnels aux puissances surfaciques qui correspondent respectivement à un maximum et à un minimum du diagramme d'interférence.

Note 2 – Un rayonnement optique est considéré comme fortement cohérent lorsque le degré de cohérence dépasse 0,88, comme partiellement cohérent lorsque ce degré est inférieur à 0,88 et comme incohérent lorsque ce degré est beaucoup plus petit que 0,88.


ar
درجة التماسك

de
Kohärenzgrad, m

es
grado de coherencia

fi
koherenssiaste

it
grado di coerenza

ko
가간섭성도

ja
コヒーレンス度

pl
stopień spójności
stopień koherencji

pt
grau de coerência

sv
koherensgrad

Publication date: 1991-10
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