TABLE OF CONTENTS The information-carrying capacity of a fiber is limited by various internal distortion mechanisms, such as signal dispersion factors and nonlinear effects. The two main distortion categories for high-performance single-mode fibers are chromatic and polarization mode dispersions, which cause optical signal pulses to broaden as they travel along a fiber. Nonlinear effects occur when there are high power densities (optical power per cross-sectional area) in a fiber. Their impact on signal fidelity includes shifting of power between wavelength channels, appearances of spurious signals at other wavelengths, and decreases in signal strength. These nonlinear effects can be especially troublesome in high-rate WDM links. Important challenges in designing such multiple-channel optical networks include
Transmission of the different wavelength channels at the highest possible bit rate
Transmission over the longest possible distance with the smallest number of optical amplifiers
Network architectures that allow simple and efficient network operation, control, and management
The design of a WDM network requires the use of proven design practices when one is selecting optical fibers, specifying component types and the values of their operating parameters, and laying out networks to mitigate performance degradation processes. Signal impairment effects that are inherent in optical fiber transmission links and which can seriously degrade network performance include these:
Dispersion, which refers to any effect that causes different components of a transmitted signal to travel at different velocities in an optical fiber. The result is that a pulse spreads out progressively as it travels along...
