中文摘要：

通过实验实现了一个2000km的16阶正交振幅调制传输系统，该系统采用后向分布式拉曼放大器对信号进行放大．单段跨距为80km，并在接收端采用数字背向传输算法补偿光纤传输过程中的非线性效应。采用分布式拉曼放大后，信号在光纤中的功率分布不再是指数衰减，采用的数字背向传输算法对此做了优化。实验结果表明．采用数字背向传输算法后，信号的Q2值提升了2．1dB。

英文摘要：

A long-haul optical fiber communication system after 2 000-km fiber transmission with 16-ary Quadrature Amplitude modulation （16QAM） format is experimental demonstrated. The system uses backward distributed Raman amplification and Digital Background Propagation （DBP） algorithm at the receiver side to compensate the nonlinear effects in fiber transmission. By adapting the distributed Raman amplification, the signal power in the fiber does not decay exponentially. The experiment results show that the proposed DBP algorithm can achieve 2.1 dB improvement of Q2-factor.