Page 474 - Fiber Optic Communications Fund
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Nonlinear Effects in Fibers 455
10
Power (mW) 5
0 1500
–200
1000
0 500 Distance (km)
Time (ps)
0
200
Figure 10.20 Nonlinear interaction between adjacent pulses. The pulses are separated by 25 ps at the input. Transmission
2
fiber is a standard single-mode fiber with =−22 ps /km. The dispersion is fully compensated in each span.
2
12
Input
10
8
Power (mW) 6 Output
4
2
0
–2 –1 0 1 2
Time (ps) × 10 –8
Figure 10.21 Optical power distribution at the fiber input and output. Fiber length = 1600 km. The parameters are the
same as in Fig. 10.20.
10.8.2 Intrachannel Four-Wave Mixing
When two or more pulses of the same channel interact nonlinearly, echo or ghost pulses are generated, as
shown in Figs. 10.22 and 10.23. This is called intrachannel four-wave mixing. In the case of interchannel
FWM shown in Fig. 10.24(a), the nonlinear interaction between the frequency components f , f , and f leads
3
2
1
