Dynamics of SHB and SDP on 9XX EDFAs: Dependence on spectral allocation of input channels

The influence of the spectral allocation of input channels on the dynamic response of three-level erbium-doped fiber amplifiers (EDFAs) governed by spectral hold burning (SHB) and site dependent pumping (SDP) is investigated, both, experimentally and theoretically. Using an experimental setup specifically designed to isolate and assess the SHB and SDP behavior we are able to validate, with a good accuracy, a mathematical model derived from the fundamental equations of the three-level amplifier. We conclude that by selecting a pump wavelength centered at 974 nm instead of 980 nm, we can reduce the power excursions by 23 %, and that by increasing the channel spacing from 100 GHz to 150 GHz the power excursions decrease by more than 20 %. Further simulations are done to investigate the behavior of SHB and SDP in an EDFA with ideal gain control. We verify that in a subband switch, changing from the red subband to the blue subband causes higher deviations than when changing from the blue subband to the red subband of the c-band. Also, in a drop scenario, the overshoots and undershoots of the surviving channel depend on the input channels spectral allocation and on the gain of the amplifier.