Experimental study of the performance of bidirectionally pumped raman fiber amplifier

The noise characteristics, gain saturation and pump power conversation efficiency of bidirectionally pumped Raman fiber amplifier (RFA) are investigated in detail. The results show that the noise characteristics of bidirectionally pumped RFA lies between that of the co- and counter-pumped RFA, and can be improved by increasing the co-gain reasonably. The saturation power of bidirectionally pumped RFA is lower than both the co- and the counter-pumped RFA and the gain saturation phenomenon becomes more serious with the increment of the ratio of the co-gain to the counter gain. Higher pump power conversion efficiency (PCE) can be achieved by increasing the ratio of co-gain to counter-gain when the total input signal power is relatively low, and by decreasing the ratio of co-gain to counter-gain when the total input signal power is relatively high.