EDFA Gain Tilt Profile Error

[AndreaDAmico]

Bug Description
The current implementation consider a given value of DGT for evaluating the Gain/Tilt profile along frequency, which provides roughly 1dB Tilt mismatch between expected and evaluated values.

To Reproduce the Bug
Steps to reproduce the behavior:

1. Consider one EDFA
2. Evaluate the DGT measuring two gain profiles with distinct values of target tilt and a fixed value of target gain (see R. D. Muro, “The er3+-fiber gain coefficient derived from a dynamic gain tilt technique”, JLT, vol. 18, no. 3, pp. 343–347, 2000. DOI: 10.
   1109/50.827506)
3. Set the measured DGT in the EDFA input
4. Compare the GNPy evaluated and the measured gain profiles

Proposed Solution
An advanced implementation of EDFA gain profile evaluation is shown in the figure.