Simulation for the effect of cascaded gain-temperature dependence on 40 channel-50 EDFA WDM link under temperature fluctuations

With the fast consumption of transmission bandwidth, the gain flattened erbium-doped fiber amplifies (EDFA) now became an essential element for realizing high capacity long-haul wavelength division multiplexing (WDM) transmission systems. Most recent development now includes long wavelength amplifiers, which can support more than 80 nm's of the wide, flat gain window when combined with the normal EDFA. There has not been serious investigation on the temperature effect on the multichannel gain of the EDFA, which could degrade even the most well-designed, gain flattened EDFA performances. Further, even for those existing few reports on this issue so far, the investigation have been restricted to a single EDFA, missing the accumulated effect of multichannel gain distortion from the cascaded EDFA systems. Part of the reason for this lack of study on the EDFA link under temperature fluctuation, lies in the complication of the experiment which require many resources in temperature-varying environments. In the paper, as a reasonable alternative for this kind of study, we numerically investigate the influence of the accumulated effect of temperature-induced, multi-channel gain distortion after a 50-EDFA chain. Results show significant reductions on the transmission distance, especially for the signal band around 1530 nm.