The standard single mode fiber link cable is made of both materials under study which the investigation of the spectral
variations of the waveguide refractive-index, n require empirical equation under the form [13]:
2
6
2
2
5
2
4
2
2
3
2
2
2
2
2 1 1
A
A
A
A
A
A
n
−
+
−
+
−
= +
l
l
l
l
l
l
(1)