Depolarized diode pump unit designed for C-band flat-gain Raman amplifiers to control EDFA gain profile

摘要

We demonstrate depolarization of pump LD to diminish PDG in Raman amplifiers in order to decrease the number of LDs. By optimizing pump wavelengths and using depolarized LD. we realize cost-effective pumping unit comprising only two LDs, to obtain a sufficiently flat Raman gain over the conventional, EDFA gain band (C-band:1530-1560nm). As an example of the application, EDFA gain tilt is controlled by means of Raman gain in DCF instead of a variable optical attenuator in an in-line amplifier, so that the gain flatness and output power can be simultaneously maintained constant against input power variation.