抽运方式对混合拉曼光纤放大器性能的影响

通过实验比较了前向抽运拉曼光纤放大器与掺铒光纤放大器组成的混合放大器、后向抽运拉曼光纤放大器与掺铒光纤放大器组成的混合放大器的性能。实验采用75km标准单模光纤作为增益介质。采用20信道(符合ITU-T建议的波分复用信号)，波长为1537．377～1560．605nm，作为混合放大器的测试信号。20信道总功率-2．86dBm，每一信道用2．5Gb／s、码长2^7-1的非归零码通过电吸收调制器(EA)进行外调制。实验结果表明，前向抽运方式混合放大器的性能优于后向抽运方式的混合放大器，其中噪声系数的改善值为2．28～6．55dB。采用前向抽运时，各信道的增益同后向抽运相比，增加值均大于5dB。但不论采取那种抽运方式，采用混合放大的形式，各信道的光信噪比均大于26．9dB。

The Influence of Pumping Configuration in Hybrid Raman Fiber Amplifier on Its Performance

The performance of forward-and backward-pumped Raman fiber amplifier/erbium doped fiber amplifier (EDFA) hybrid amplifiers was experimentally compared. 75 km standard single mode fiber (SSMF) was employed as the transmission line. 20 channels in C-band with a total power of -2.86 dBm, ranging from 1537.377 to 1560.605 nm on the ITU-T grid were used as the incident signals of hybrid amplifiers. Each channel was modulated by an electro-absorption (EA) modulator using a 2.5 Gb/s nonreturn-to-zero (NRZ) format, with a 27-1 long pseudo-random bit sequence (PRBS) signal. Experimental results have suggested some of relative merits of forward-pumped RFA/EDFA hybrid amplifiers. The improvement of noise figure (NF) arranged from 2.24 dB to 6.55 dB. The gain increase was higher than 5 dB for any channel in forward-pumped hybrid amplifiers in comparison with backward-pumped hybrid amplifiers. However, the optical signal-to-noise ratio (OSNR) is higher than 26.9 dB in either pumped configuration for hybrid amplifiers.