Supercontinuum (SC) from optical fibres [1-3] has recently gained significant interest in the development of new broadband optical sources for applications requiring a tunable, bright source operating in the pico- to nano-second range for communications. Typically, ultra-short pulses are generated using bulk laser systems such as Titanium-Sapphire (Ti-Sapphire) lasers, but require critical optical alignment and many other sophisticated optical techniques, thus making these systems complicated, expensive and not suitable for laboratories with a limited budget. An alternative approach is to generate these short pulses using rare-earth doped fibres, which would allow for the development of cheap, compact, stable and easy to maintain sources for SC generation [4, 5]. Such a system will also find applications in the areas of optical coherence tomography [6], spectroscopy [7] and frequency metrology [8]. The process of SC generation is normally done in a non-linear fibre, whereby SC is a complex nonlinear phenomenon that is characterized by the dramatic spectral broadening of intense light pulses passing through a nonlinear medium. Recently, more attention has been paid to nonlinear fiber with longer infrared transmission windows such as Highly Nonlinear Fiber (HNLF), Photonic Crystal Fiber (PCF) and Chalcogenide Fiber. Therefore, the Few Mode Fiber (FMF) is the alternative fiber for infrared transmission window. This fiber possess a high refractive index and can support high optical power than Single Mode Fiber (SMF). In this book, the feasibility of FMF transmission systems by studying the supercontinuum generation in two modes is presented. In most reported experiments, SC generation is observed by higher-order mode excitation in other nonlinear fiber. However, broad tunable soliton and associated dispersive wave sources by two modes in FMF is also investigated.

中文翻译：

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用少模光纤生成八度跨度超连续谱

来自光纤的超连续谱 (SC) [1-3] 最近在开发新的宽带光源方面引起了极大的兴趣，这些光源需要在皮秒到纳秒范围内运行的可调谐明亮光源进行通信。通常，超短脉冲是使用钛蓝宝石 (Ti-Sapphire) 激光器等体激光系统产生的，但需要严格的光学对准和许多其他复杂的光学技术，因此使这些系统复杂、昂贵且不适合实验室预算有限。另一种方法是使用稀土掺杂光纤产生这些短脉冲，这将允许开发廉价、紧凑、稳定且易于维护的 SC 产生源 [4, 5]。这样的系统还将在光学相干断层扫描 [6]、光谱学 [7] 和频率计量学 [8] 领域得到应用。SC 生成过程通常在非线性光纤中完成，其中 SC 是一种复杂的非线性现象，其特征在于通过非线性介质的强光脉冲的光谱显着展宽。近来，高非线性光纤（HNLF）、光子晶体光纤（PCF）和硫族化物光纤等具有较长红外传输窗口的非线性光纤受到越来越多的关注。因此，少模光纤（FMF）是红外传输窗口的替代光纤。这种光纤具有高折射率，并且可以支持比单模光纤 (SMF) 更高的光功率。在这本书中，通过研究两种模式的超连续谱产生，介绍了 FMF 传输系统的可行性。在大多数报道的实验中，通过其他非线性光纤中的高阶模式激发观察到 SC 的产生。然而，还研究了 FMF 中两种模式的宽可调谐孤子和相关色散波源。