Erbium-doped fiber amplifiers design strategies to optimize capacity in submarine systems

Abstract

We revisit the design strategies of erbium-doped fiber amplifiers (EDFA) in wavelength division multiplexing (WDM) submarine links over transoceanic distances. We particularly investigate the optimization of EDFA settings such as fiber length, optical bandwidth and population inversion to maximize the power efficiency and/or achievable information rate (AIR) at fixed span length. When optical bandwidth is fixed, we show the existence of a unique EDFA optimum setting whatever the pump power, provided Kerr-effect is overlooked. When accounting for Kerr-effect, the EDFA parameters can be adjusted to improve AIR as pump power increases. We also show a performance enhancement when working with a variable bandwidth design at very-low and very-high pump powers.