Amplification of spontaneous emission in erbium-doped single-mode fibers

Abstract
Amplification of spontaneous emission (ASE) in erbium-doped single-mode fiber amplifiers operating at lambda =1.53 mu m is studied theoretically and experimentally. The ASE noise spectra obtained from the theory are found to be in excellent quantitative agreement with the experimental data. The observed changes in ASE spectral shapes under different population inversion conditions are also explained. The model may be used to evaluate the performance of erbium-doped fiber lasers as well as to assess the noise characteristics of erbium-doped fiber amplifiers as applied to wavelength-division multiplexing optical communications.