Measurement Procedure for the Inverse Spectral Hole Burning Characteristics of Erbium-Doped Fiber Amplifiers (EDFA)

We propose a novel measurement procedure to characterize the inhomogeneous line broadening of EDFAs. It aims to collect spectroscopic data that is required for the development of physical simulation models. Such models are expected to have the capability to predict spectral hole burning (SHB) characteristics precisely in a wide range of operating conditions. We have developed a novel implementation of the spectral subtraction technique that keeps the gain constant at the wavelength of the saturating signal. It allows to distinguish the contributions of distinct erbium ion groups in different sites to the gain spectrum more easily. Exemplary measurement results from our novel approach are compared with results obtained with the conventional procedure. The impact of inhomogeneous line broadening is clearly visible and our novel approach avoids to impose restrictions on amplifier operating conditions at multiple wavelengths.