Optical soliton communication-Application to the long distance and high data-bit communication-

我们从理论上得到了一种新的孤子（准孤子），它具有比理想孤子更好的传输特性。通过适当的色散映射可以产生准孤子。准孤子允许比孤子小得多的脉冲间隔，因此它可以增加每个波长信道的比特率。此外，它的稳定脉冲形状比所谓的色散管理孤子更适合于OTDM网络。从理论上研究了色散周期性变化光纤中色散管理孤子在波长复用应用中的特性与色散差的关系，实验结果表明，频率偏移随Δ L的变化呈周期性减小和消失的趋势，并利用滑动滤波器对2 × 10 Gbps WDM光孤子进行了传输实验通过与Chalmer's University的Andreckson教授的合作，证明了光源信噪比的降低会使孤子的传输特性变差。我们成功地传输了10 Gbps的光孤子超过16,000公里，误码率小于10^<-9>。此外，我们还利用梳状色散管理技术实现了放大器间距为80 km的10 Gbps孤子在2,000 km的距离上的传输，并利用诱导的调制不稳定性，与莫斯科大学的Chernikov博士合作，成功地产生了自相关宽度为3.7 ps、重复频率为86.8 Ghz的近傅里叶变换极限孤子脉冲。长谷川教授的发明。

We obtained theoretically a new soliton (the quast-soliton) having a much better transmission properties than an ideal soliton. The quasi-soliton can be produced by means of a proper dispersion mapping. The quasi-soliton allows much smaller pulse spacings than an soliton thus it can increase bitrate per a wavelength channel. In addition its stationary pulse shape is much more suited for OTDM networks than the so called dispersion managed solitons.Properties of dispersion managed soliton in a fiber having periodic variation of dispersion were theoretically studied in its application for wavelength multiplexing as a function of the difference of the dispersion, DELTAD.The frequency shift was found to decrease and disappear periodically as a function of DELTAD.Experiments of transmission of 2x10Gbps WDM solitons were performed with sliding filter control and confirmed the transmission property depends on the wavelength characteristics of EDFA.With collaboration of Prof.Andreckson of Chalmer's University, it was demonstrated that the decrease of S/N ratio of the light source deteriorate the transmission property of a soliton. We succeeded transmission of 10Gbps solitons over 16,000km with bit error rate of less than 10^<-9>. In addition, we could transmit 10Gbps solitons having amplifier spacing of 80 kms over a distance of 2,000km by means of comb type dispersion management.With collaboration of Dr. Chernikov at lmperial College, we could succeed generation of near Fourier transform limited soliton pulse having autocorrelation width of 3.7ps and repetition rate of 86.8Ghz with the use of the induced modulational instability, an invention of Prof.Hasegawa.