Effect of injection of C-band amplified spontaneous emission on two-stage L-band erbium-doped fiber amplifier

摘要

An effect of injection of conventional-band amplified spontaneous emission (C-band ASE) on a two-stage long wavelength band erbium-doped fiber amplifier (L-band EDFA) is demonstrated. It uses two circulators and a broadband fiber Bragg grating (FBG) to route unused C-band backward ASE from the second stage back to the input end of the first stage of the amplifier. The amplifier gain is clamped at 15.5 dB and the saturation power increases from -13 dBm to -8 dBm with injection of the C-band ASE. The gain level can be controlled to be in the range from 15.5 to 16.8 dB by varying the variable optical attenuator (VOA) loss from 0 to 20 dB without much variation in noise figure. These results show that the injection of C-band ASE can be used to clamp the L-band gain in a two-stage L-band EDFA, which has higher gain compared to a single stage.