随着数字业务的飞速增长，光传送网技术OTN由于具有大容量、远距离传送的优势，成为下一代传送网发展 的主要方向。在大容量OTN超长距离传输中，由于损耗、噪声、色散、非线性效应等影响，造成信号质量下降、误码率增加。 光放大器、色散补偿、前向纠错、编码调制等关键技术能够有效解决这些问题，提高信号的质量、降低误码，提高系统可靠性，实 现大容量和超长距离传输。

With the rapid growth of digital business, OTN technology becomes a main development direction of the next generation of transport network because of its large capacity and long-distance transmission. In large capacity of ULH, the signal quality declines and bit error rate increases due to the loss, noise, dispersion and nonlinear effect. The technologies of optical amplifier, dispersion compensation, FEC and code modulation can effectively solve the problems, improve the signal quality and system reliability, reduce the bit error rate, and achieve large capacity and long distance transmission.