Theoretical and experimental study of self-filtering effect in concatenated erbium-doped fiber amplifiers

This paper describes the self-filtering effect which appears in concatenated erbium-doped fiber amplifier (EDFA) systems. Employing a theoretical model we observed how the self-filtering wavelength is affected by the variation of some EDFA parameters, such as gain, fiber composition, pump wavelength and temperature. By a recirculating loop experiment which simulates a concatenated repeater transmission system, we measured the evolution of the amplified spontaneous emission (ASE) spectra with the number of circulations, and with the loss of the loop. We found a good agreement between the theoretical simulations and the experiments