A theoretical study of transient behavior of gain-clamped erbium doped fiber amplifiers in WDM systems

We present a detailed theoretical analysis of the transient behaviors of erbium doped fiber amplifiers (EDFA's) in wavelength division multiplexed (WDM) optical networks by using a single dynamic model. While the amplifier is longitudinally divided into n subsections to take into account the longitudinal spatial hole-burning, and fully resolved amplified spontaneous emission (ASE) spectra. The tradeoff between accuracy and computational complexity leads an optimum n = 10 through our investigation. Using this model, a gain-clamped EDFA in WDM systems has been investigated. The numerical simulations tell us that the lasing wavelength, cavity loss and traveling directions are important constraints for an optimum design. The available laser wavelength and cavity loss combinations are proposed, while the co- and counter-traveling lasing schemes are compared. It's demonstrated that the longitudinal population inversion profile determines the dynamic gain and noise performance in both conventional and gain-clamped EDFA.