
28 Optical Fiber Communication Systems with MATLAB
®
and Simulink
®
Models
Cladding glass n
2
(b)
Core glass n
1
> n
2
Air n
0
= 1
D = 125 μm
2W
0
= 10 μm
Cladding glass n
2
n
2
n
1
n
2
(c)
Air n
0
= 1
Low order
Cladding
Cladding glass n
2
Core glass n
1
(r) ≥ n
2
glass n
2
n
2
n
2
n
1
(r)
High order
2a = 50 μm
(a)
LP
01
va
LP
01
LP
21
V
LP
11
LP
31
LP
12
LP
02
2.405(d)
0
0
1
2
3
4
1 2 3 4 5 6
ua
FIGURE 2.6
(a) Guided modes as seen in the transverse plane of a circular optical ber. (b) “Ray” model of light wave
propagating in single-mode ber. (c) Ray model for multimode graded-index ber. (d) Graphical illustration of
solution for eigenvalues (propagation constant—wave number of optical bers)