Pump wavelength's influence in erbium-doped fibre amplifier performance

The erbium doped fibre amplifier (EDFA) has been extensively developed due to its compatibility with existing optical fibre systems, low insertion loss, low crosstalk, high gain, polarization insensitivity and low noise figure (NF). The preferable pumping wavelengths for EDFAs are 980 nm and 1480 nm, which creates a 3-level and 2-level system respectively. The advantages of 980 nm as a pumping wavelength compared to 1480 nm are full ion inversion, a lower noise figure and negligible excited state absorption (ESA). A model simulating the 3-level energy system of the Er-doped fibre amplifier (EDFA) in a co-propagating configuration for the 980 nm pump wavelength range is presented and discussed. The characteristics being considered for performance are gain, output signal power, excess pump power and noise figure. The theoretical model is developed to numerically solve the coupled differential equations of the pump and signal power evolution along the fibre. This numerical model uses the relaxation technique for convergence, whereas the differential equations are solved using the simple Euler method.