中红外超连续谱激励中畸形波稳定、选择性激发及精确控制研究

Stabilization, selective excitation and precise control of optical rouge wave (RW) are the key to break through the limitation of broadening and stability of mid-infrared supercontinuum (Mid-IR SC). In this project, we focus on the technological frontier of thulium-doped light sources and Mid-IR SC, and the RW generation in the Mid-IR SC. The generation mechanism of RW under induced modulation instability is studied, and the RW evolutionary theoretical model in chalcogenide fiber pumped by thulium-doped laser is first carried out. First, the life cycle of RW is studied in depth, and then the precise control mechanism of RW is explored to solve the instability problem such as the mutation of spectrum. Second, the realization of stable transmission and selective excitation of RW is studied, so as to enhance the energy at long wavelength and expand the spectral width. The MoSe2 and modulator-based thulium-doped pulse pump source and signal source are utilized to pump the chalcogenide fiber to realize the stability (100 m), selective excitation (150 nm) and precise control of RW. For RW in Mid-IR supercontinuum excitation, we strive to achieve a quantitative description and solve the problem of effective control. The research results of the project can provide theoretical and practical guidance for resolving the problems related to spectral mutation and broadening of the Mid-IR SC, which will greatly promote the research and application of the Mid-IR SC technology.

光学畸形波（RW）的稳定、选择激发及精确控制，是突破中红外超连续谱展宽及稳定性问题瓶颈限制的关键环节。本项目紧抓掺铥光源、中红外超连续谱的技术前沿，紧扣中红外超连续谱产生中RW问题，研究在诱导调制不稳定性条件下RW的产生机理，并率先进行掺铥激光泵浦硫系光纤生成RW演化理论模型研究。首先，深入研究RW的生命周期，进而探索RW精确控制机制，解决光谱产生突变等不稳定问题。第二，探索RW稳定传输及选择激发的实现方式，进而提升光谱长波长处能量，拓展光谱宽度。本项目将利用搭建的基于MoSe2和调制器的掺铥脉冲泵浦源和信号源泵浦硫系光纤，实现RW稳定（100 m）、选择激发（150 nm）及精确控制。对于中红外超连续谱激励中的RW，力争实现定量描述，并解决有效控制问题。项目研究成果，可为中红外超连续谱光谱突变及展宽等相关问题的解决提供理论和实践指导，将会极大地推动中红外超连续谱技术研究及应用水平的提高。

自上世纪七十年代，超连续谱被首次观测到以来，如何再进一步拓展超连续谱的带宽同时增加其稳定性一直受到广泛的关注与研究。而随着2 μm波段泵浦光源和非石英光纤的发展，超连续谱光源的带宽也逐渐扩展至中红外波段。中红外超连续谱光源在基础科学、通信与医疗等领域都有广泛的应用，尤其是光学测量、光谱学与无损检测等方面对中红外超连续谱光源的稳定性、带宽、平坦度和功率都提出很高的要求。因此，如何提高光谱稳定性、如何将波长拓展至更长波长处、并增加生成超连续谱的平均功率，这都是中红外超连续谱所面临的问题。.本项目紧跟中红外超连续谱产生的技术前沿，紧扣中红外超连续光谱产生中畸形波问题，研究了基本正弦函数形式和振幅调制形式的色散振荡光纤对中红外超连续谱、畸形波的调控效果；探究了在硫系光纤的反常色散区入射泵浦脉冲并在调制不稳定性增益峰的位置入射种子光时，种子光时延的变化如何促进或抑制中红外超连续谱中畸形波的形成及控制；探究了在泵浦光与种子群速度匹配的条件下，分别考虑两束光各自色散和非线性效应时，两束光之间波长差的变化对中红外超连续谱中畸形波的控制起到何种影响。项目对于推进中红外超连续谱研究，进一步促进超连续谱在各个领域中的实际应用，均具有很重要的意义。