into a Si-SiO2 chip SO that the additional loss due to interfacing is minimum. The parameters of the line are not reported since they are identical to the IM case. In order to try to achieve the maximum possible distance, we also add another couple of Raman pumps into the SSMF from the receiver with the intention of limiting the signal attenuation SO to decrease the global noise amount. Since the DCF is used also for transmission of the pumps into the SSMF fiber to increase the system length, the pumps for the SSMF have to be located in the far TABLE 6.14 Parameter Values for the All Raman Single Span Differential Phase Shift Keying System Channel speed 10 Gbit/s Optical bandwidth of the DWDM comb Extended C band Modulation DPSK NRZ Number of channels Channel spacing 100 GHz Transmitting chain Source laser emitted power 16 dBm Source laser linewidth 500 kHz Mach Zehnder lithium niobate phase modulator loss Multiplexer (multistage AWG X 80) loss Patchcords, connectors, monitoring taps loss Detection chain High-efficiency APD sensitivity @ 10 Gbit/s -28 dBm Beam splitters + delay line + insertion in SiO2 Demultiplexer (multistage AWG X 80) loss Patchcords, connectors, monitoring taps loss Power per channel on the APD -20 dBm Telecommunication Networks terminal of the system and propagated up to the insertion point, that is, for 20 km, into a dedicated fiber. This system is called remote pumping. Since the loss of the SSMF at the pump wave- length is about 0.3 dB km; 20 km propagation is equivalent to 6 dB loss, that have to be added to the 3 dB insertion loss. Almost no loss there is at the insertion of the pump into the SSMF that transport them since we imagine that the pump lasers are sold packaged and the nominal power is the power in the fiber pigtail. With these figures in mind, we have to add 9 dB to the remote pumps power to define the power of the pump lasers. The scheme of the system is reported in Figure 6.34 and the single-channel power behavior Figure 6.35. The Raman gain of this new amplifying section 