L-band EDFA gain dependence on the return loss of the components in the amplifier input port

We show experimentally and via simulations that a broadband end reflector that creates a reflectivity as small as 0.01% (RL = 40 dB) in the components in the input port of an L-band EDFA can strongly change the amplifier gain behaviour. This means that good characterizations of this parameter is important to obtain good agreement between simulations and measures and to correctly project EDFAs. Moreover, this fact can be used to improve the performance of the amplifiers. Different studies must be done in this sense because the correct value of the RL will depend on the desired characteristics of the amplifier.