EDFA in-line amplifier and of the last EDFA us is the overall gain or loss of the transmission chain, from the exit of the booster to the exit of the last EDFA and can be expressed as (6.79) where Ps(0) is the signal power at the output of the booster Transmission Systems Architectures and Performances Since, for all reasonable designs, it is the peak power of the link; it has a value PM prescribed by the nonlinear effects that in our case we have tentatively set as 5 dBm The condition on the maximum peak power can be written as PlaTGB==MM (6.80) where P1 is the power emitted by the laser source aT is the whole loss between the power source and the input of the EDFA booster; in our case, the losses of the multiplexer, the mux, the connectors, and the monitoring taps The condition on the receiver sensitivity can be written as (6.81) Solving (6.80) with respect to GB and (6.81) with respect to Gp and remembering the definition of E, the expression of SNo becomes a function of two unknown variables: GE and GR. Generally, since Raman distributed amplification makes less noise and operates on a signal of lower level, the optimization consists in maximizing GR, taking into account the limitations in the available power of the pumps and of the possibility of choosing different types of DCF, and then selecting consequently GE. At this point the dimensioning of the line is ended, and all the line parameters are sum- marized in Table 6.8. TABLE 6.8 Line Parameters after the Draft Design of the Ultra-Long-Haul 10 Gbit/s System General EDFA noise factor Solution Power of the first pump 330mW Power of the second pump 290mW Wavelength of the first pump 1430nm Wavelength of the second pump 1400 nm Average power in a span -11.2 dBm Booster EDFA gain In-line EDFA gain Raman gain Preamplifier EDFA gain 11 dB Two Stages EDFA Solution Average power in a span -6.61 dBm EDFA booster gain First stage of in-line EDFA gain (also the 11.4dB preamplifier) Second stage of in-line EDFA gain Second stage EDFA preamplifier gain 11 dB Telecommu