en the availability of higher Raman gain fibers with relatively low loss. As an example, commercial DCF has a Raman efficiency almost 10 times greater compared to standard single-mode fiber. Moreover, new Raman gain fibers continue to be introduced commercially with different dispersion profiles and dispersion slopes. A second key development for Raman amplifiers has been the availability of high pump power laser diodes. Commercial laser diodes are available with more than 800 mW output powers with the ability to inject more than 500 mW in an SSMF, and more than 1 W of fiber injected power has been realized in experimental systems. Using sufficiently powerful pump lasers at the right wavelengths, in principle, it is possible to shape the Raman gain to achieve a sufficiently high gain over all C and L bands [66]. For example, with two pumps a sufficient equalization of the Raman gain over all the band (35nm) can be achieved and better results can be obtained with three pumps. Equalization of the gain over 60nm (C and L bands) can be achieved using three or four pumps. Telecommunication Networks All the pumps adopted in this application are high-power semiconductor lasers. However, in using such devices, some issues could arise that does not exist when using the much less powerful EDFA pumps. With a power of some Watt traveling through the fiber within 1400 and 1450 nm, con- nectors adjacent to the amplifier have to be ready to support a great stress and particular attention has to be devoted to their correct alignment. Moreover, pump reflections can be dangerous and particular care has to be paid to reduce the reflection coefficients of the components along the pump path. A third point in using semiconductor laser pumps is that Raman gain is polarization dependent; thus, in order to equalize the gain over all the incoming signal polarization, it is necessary to have an unpolarized pump. This can be obtained from a semiconductor laser, which emits a LP field either with a concentrated element or, more frequently, i