Study on generation and propagation of sub-20 femto-second optical fiber soliton pulses

高阶光纤孤子效应常用于超短脉冲的压缩。实际上，通过该方法可以产生20飞秒（fs）或更短的脉冲，这对应于1500 nm电磁波的仅四个周期。为了阐明在时域下限的最终性能及其限制因素，我们利用了高阶光纤孤子压缩的现象。此外，我们讨论了优化的框架，从而产生的光谱形状的光通信光源的多载波。我们得出的结论（包括一些新的知识）是，四阶色散是超短光纤孤立子脉冲最终特性的一个重要特征，因为它导致了时域中的限制因素并影响了高带宽超连续谱的产生。以下是本研究中获得的结果。( 关于我们 1)成功地导出了迄今为止报道的最短光纤孤子脉冲。其时间周期为15.6 fs。我们认为，光纤超快光子学中新的时间域已经建立。(2)We指出四阶色散通过反常色散带宽限制了光纤孤子的最终脉冲宽度。这已被实验证实，通过系统的调查在各种条件下产生的脉冲的时间宽度。事实上，这是第一个明确的证据，表明光纤的四阶色散效应以真实和清晰的方式出现。(3)On另一方面，我们通过实验发现四阶色散效应可以产生高效的宽带参量增益。并对这一现象进行了理论解释。(4)On在（3）结果的基础上，我们提出了几种宽带光谱产生方法的新方案。少

The effect of higher order fiber-optical soliton is often used for ultrashort pulse compression. Indeed, 20 femto-second (fs) pulse generation or shorter is possible through the method, which corresponds to only four cycles of 1500 nm electromagnetic wave. In order to clarify the ultimate performance and its limiting factors in the lower boundary of the time domain, we have utilized the phenomena of higher order fiber-optical soliton compression. Furthermore, we discussed on the framework for optimization of the spectral shapes thus generated for optical communication light source of multiple carriers. We have reached the conclusion, which includes some newly achieved knowledge, that the fourth order dispersion is an important feature for the ultimate characteristics of ultrashort fiber-optic soliton pulses since it leads to the limiting factor in the time domain and affects the high bandwidth super-continuum generation. The followings are the results obtained in the present research.( … More 1)The shortest fiber optic soliton pulse ever reported has been successfully derived. Its time period is 15.6 fs. We believe that the new temporal area in the fiber-optic ultrafast photonics has been established.(2)We pointed out that the ultimate pulse width of fiber-optical soliton is restricted by the fourth order dispersion through the anomalous dispersion bandwidth. This has been confirmed experimentally by means of systematic investigation on temporal widths of generated pulsed under a variety of conditions. Indeed, this is the first clear evidence that the fourth order dispersion effect of an optical fiber appears in a realistic and clear manner.(3)On the other hand, we found out experimentally that the fourth order dispersion effect can give rise to efficient parametric gain generation of broadband. Also, the theoretical explanation for the phenomena has been established.(4)On the basis of the results of (3), we demonstrated a few new schemes for broadband optical spectrum generation methods. Less