Studies on ultra high-speed optical pulse transmission using dispersion-managed solitons

超大容量骨干网络的使能技术分为两大类：大容量传输技术和网络节点的光交换技术。在数据传输方面，波分复用(WDM)技术的最新进展使传输容量急剧增长，最高可达太比特/秒，WDM系统的传输容量用每波长比特率和波长数的乘积来表示。最近传输能力的增加主要是由波长数量的增加提供的。然而，即使在光学领域，频率资源也是有限的，并且波长数量的过度增加导致了对光学系统的复杂的监控和维护。为了克服这些困难，我们不得不提高每个波长的比特率，但这并不容易，因为光纤中的各种效应会对…产生干扰脉冲宽度越短，脉冲传播越多。WDM系统的传输容量由每个波长的比特率和波长数的乘积来表示。最近传输能力的增加主要是由波长数量的增加提供的。然而，即使在光学领域，频率资源也是有限的，并且波长数量的过度增加导致了对光学系统的复杂的监控和维护。为了克服这些困难，我们必须提高每个波长的比特率，但这并不容易，因为随着脉冲宽度的变短，光纤中的各种效应会干扰脉冲的传输。在本研究中，我们研究了利用色散管理孤子(DMS)的传输技术，它可以抵抗色散、非线性光学效应和高阶色散，并追求传输速度的极限。为此，我们研究了DMS的基本特性和DMS传输系统的设计准则。主要研究结果如下：(1)数值研究了色散、偏振模色散和高阶色散对DMS脉冲的影响，发现通过优化脉冲能量可以实现光脉冲的稳定传输。(2)在数值研究的基础上，搭建了一个40Gbit/S远距离传输系统，并利用数字毫米波脉冲实现了几千公里的无差错传输。(3)提出并论证了色散监测新技术和色散补偿技术，这是实际高码率DMS传输系统所需的关键技术。较少

Enabling technologies for ultra-high capacity backbone networks are divided into two categories ; the high-capacity transmission technology and the optical switching technology at network nodes. As for the data transmission, the recent progress in the wavelength-division multiplexing (WDM) technique has achieved the drastic growth of the transmission capacity up to tera-bit/sec.The transmission capacity of WDM systems is expressed by the product of the bit-rate per wavelength and the number of wavelengths. The recent increase in the transmission capacity has been provided mainly by the increase in the number of wavelengths. Even in the optical region, however, the frequency resources are limited, and the excessive increase in the number of wavelengths leads to the complicated supervision and maintenance of optical systems. In order to cope with these difficulties, we have to increase the bit-rate per wavelength, but it is not easy because the various effects in optical fibers disturb t … More he pulse propagation as the pulse width becomes short. The transmission capacity of WDM systems is expressed by the product of the bit-rate per wavelength and the number of wavelengths. The recent increase in the transmission capacity has been provided mainly by the increase in the number of wavelengths. Even in the optical region, however, the frequency resources are limited, and the excessive increase in the number of wavelengths leads to the complicated supervision and maintenance of optical systems. In order to cope with these difficulties, we have to increase the bit-rate per wavelength, but it is not easy because the various effects in optical fibers disturb the pulse propagation as the pulse width becomes short.In this study, we have investigated the transmission technique using dispersion-managed soliton (DMS) which can withstand the dispersion, nonlinear optical effects, and higher-order dispersion, and pursued the ultimate limit of the transmission speed. For this purpose, we've investigated the fundamental properties of DMS's and the design guideline of DMS transmission systems. The results are summarized as follows; (1) we numerically studied the influence of the dispersion, the polarization-mode dispersion, and higher-order dispersion on DMS pulses and found that the stable transmission of optical short pulse was possible by optimizing the pulse energy. (2) On the basis of the numerical study, we constructed a 40-Gbit/s long-distance transmission system, and demonstrate the error-free transmission over several thousands of kilometer by using DMS pulses. (3) we proposed and demonstrated novel techniques for dispersion monitoring and dispersion compensation technique, which are key technologies required for practical high-bitrate DMS transmission systems. Less