A novel method to improve noise figure for a wide bandwidth single stage L-band EDFA

To improve the noise characteristics and to increase the power conversion efficiency in the wide bandwidth single stage L-band EDFA, we proposed a new configuration of the EDFA which transmits 1.56 /spl mu/m back-propagating noise suppression light to reduce the ASE generated around the output end of the EDF. As a result, the power conversion efficiency improved more than twice, and the NF was reduced to 3.6 dB compared to the efficient of conventional L-band EDFAs. Determining the wavelength for optimal back-propagating noise suppression light remains to be studied.