design undersea optical transmission system

An undersea optical transmission is to be designed. the undersea distance is 220km. the bit rate is 40 Gb/s and optical receiver with a sensitivity of -20dbmis available . optical amplifiers EDFA and ROA are considered with the following parameters -fiber types : SSFM and DCF (with dispersion factor of -85ps/(nm km)and effective area of 17) ;EDFA :gain=20db and NF=5db ;output power :saturated output power =15dbmfor booster amplifier type and +10dbm for optical preamplification type ; ROA :pump power =500mW, gain in SSFM =12db over a 20km distributed distance of the fiber and NF=3db for both co-and contra directional pumps. 1)sketch a proposed structure of the transmission link . 2)obtain a diagram of the signal power or the power budget over the link. 3) obtain the dispersion budget over the link.