On the optimization of the gain distribution of transmission lines with unequal amplifier spacing

We find the distribution of the gain of in-line amplifiers in a transmission system with unequal amplifier spacing that minimizes the effects of the optical nonlinearity. The optimum map gives rise to the minimum average power for a given signal-to-noise ratio (SNR) at the receiver, and the minimum SNR for a given average power. In the optimum map, the amplifier gains are such that the power in the middle of each passive fiber segment is constant along the line.