Amplified spontaneous emission in high-power, Er^3+–Yb^3+ codoped fiber amplifiers for wavelength-division-multiplexing applications

Abstract

Amplified spontaneous emission (ASE) in high-power, gain-flattened, Er3+–Yb3+-codoped fiber amplifiers (EYDFAs) is analyzed by use of a rate-equations model. Numerical results suggest that the ASE noise is more significant in L-band EYDFAs, depending on the pump configuration. ASE noise in C-band EYDFAs is considerably weaker and is almost independent of the pump configuration. Increasing the cladding area improves the noise figure properties, provided that the pump and the signal are injected at opposite ends (backward pumping). The dependence of the noise figure on the Yb3+ concentration and on the pump wavelength in L-band EYDFA is also analyzed.