Δ= n 1 2 − n 2 2 2 n 1 2 MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbbjxAHXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeqabiGaciGacaqadmaadaqaaqaaaOqaaiabgs5aejabg2da9maalaaabaGaamOBamaaDaaaleaacaaIXaaabaGaaGOmaaaakiabgkHiTiaad6gadaqhaaWcbaGaaGOmaaqaaiaaikdaaaaakeaacaaIYaGaamOBamaaDaaaleaacaaIXaaabaGaaGOmaaaaaaaaaa@414D@
where n1 and n2 are, respectively, the maximum in the core and the refractive index of the innermost homogeneous cladding
où n1 est l'indice de réfraction maximal dans le coeur et n2 l'indice de réfraction de la gaine homogène la plus interne