Hi Fayiqa,
I think going towards high launch power or transmitter power is definitely help you in some aspects including as you have mentioned. but in most of the cases in our design in optisystem we have not considered the fiber nonlinearity but in practical systems it is mostly required to make the transmitter power low (in terms of power budget also). so you have take into consideration all the probable issues (such as temporal variation in the refractive index). Nonlinear effects in optical fibers occur due to (1) change in the refractive index of the medium with optical intensity and, (2) inelastic scattering phenomenon. Thanking you.
Regards,
Dhiman