实验研究了1425 nm和1453 nm双波长反向抽运50 km单模光纤的分布式光纤拉曼放大器(RFA)。利用改进的时域消光法测量了放大器的输出特性和光学信噪比(OSNR)随开关增益的变化关系。在C波段(1530～1564 nm)内,测得放大器的开关增益约为13 dB,增益不平坦度小于±0.6 dB,相对于双瑞利散射(DRS)噪声的光学信噪比为45 dB,总的光学信噪比为39 dB。同时还测量了信号光经过二级级联分布式光纤放大器传输后的特性,结果表明,与一级光纤拉曼放大器结构相比,二级放大器的开关增益和不平坦度都增大了一倍,而输出的光学信噪比减小了约2 dB。

Backforward-pumped distributed Raman fiber amplifier (RFA) by 1425 nm and 1453 nm is experimentally studied in this paper, and its performance is measured by using the modified time-domain extension method. In the C-band (1530～1564 nm), the on-off gain of the amplifier is measured to be about 13 dB, the gain ripple is less than ±0.6 dB, the optical signal-to-double Rayleigh scatter (DRS)-noise ratio (OSNRDRS) is about 45 dB, and the optical signal-to-noise ratio (OSNR) is about 39 dB. The performance of a dual-stage distributed RFA is also investigated and the results show that the on-off gain and gain ripple are twice as large as those of a single-stage RFA, and the OSNR is about 2 dB lower compared with the single-stage one.