Investigation of Spectral Tilt and OSNR in Cascade of EDFA with Linear Signal Power Pre-emphasis

This work investigates the relationship between signal spectral tilt and OSNR of channels at the output of an EDFAs cascade as a function of a pre-emphasis in the input. We performed simulations using 40 x 256 Gbits/s PM-16QAM modulated channels and by applying a linear power preemphasis in a dB scale on all channels at the transmitter. We implemented the power pre-emphasis using a WSS at the transmitter. The results show that there is an almost linear relationship between the applied pre-emphasis and the signal spectral tilt, but the compensation is not straightforward. The results also show that by minimizing the tilt at the output of the cascade, the minimum OSNR among all channels can be severely penalized due to power attenuation in the preemphasis process.