【作者】 张祥；

【导师】 章礼富；

【作者基本信息】 深圳大学 ， 工程硕士（专业学位）， 2020， 硕士

【摘要】 随着光纤制备技术的进一步发展,各种非线性光纤被成功制备,促使了非线性光纤光学的这一领域的不断发展。光纤中非线性效应的调控是近些年非线性光纤光学领域的研究热点之一。脉冲在光纤中传播时不可避免地会受到高阶线性和非线性效应的干扰,从而导致如喇曼孤子自频移、三次谐波产生、四波混频、色散波辐射等非线性现象,这些非线性现象为非线性频率转换、超连续谱产生、数模转换等应用提供了新的视角。光学脉冲成形技术可以将超短脉冲调整为复杂的波形,以满足实际需要。谱相位调制法可以在不影响谱分布的前提下,对脉冲的时域波形进行调整,为调整和控制光纤内非线性效应提供了新的可能。本文通过对初始输入脉冲进行谱相位调制,通过数值模拟和理论解析的方法,对光纤中的非线性效应展开了研究。首先,我们研究了光纤中喇曼散射效应对艾里与孤子相互作用的影响。我们发现艾里孤子相互作用后会融合在一起,且融合点的位置可以通过改变艾里的拖尾方向来控制。这种控制使我们能够产生具有不同减速度的艾里孤子。与两个孤子相互作用情况不同,当前沿孤子被加速艾里脉冲代替时,喇曼诱导的孤子自频移被显著增强,而对于减速艾里脉冲则被轻微抑制。这些特征归因于非对称艾里脉冲的拖尾的振荡方向可调。我们通过互相关频率分辨门技术明确的揭示了这些过程。我们还研究了艾里脉冲含有初始啁啾时其啁啾对喇曼诱导的孤子自频移的影响。我们的研究结果不仅提供了一种新的操控喇曼诱导的孤子自频移的方法,而且可能有助于改进超连续谱产生过程中孤子融合事件的控制,以及光学怪波和巨型色散波的形成。随后,我们研究了谱相位调制整形脉冲研激发色散波的规律。我们发现脉冲在光纤中传输时激发的色散波可以通过调整初始输入脉冲的光谱相位来进行控制。同时,利用二阶和三阶谱相位调制得到的可调谐的非对称振荡脉冲,我们实现了一个多重激发的过程,极大的提高了色散波的能量。在不对称脉冲的多个峰值与孤子的连续碰撞中,我们给出了相应的相位匹配条件推导出的色散波频率,可以发现理论与数值实验较好的吻合。我们的结果提供了一种控制光纤中色散波发射的新方法,这可能是开发用于光谱学应用的新型光源(宽带超连续谱产生或红外频率梳)的新策略。更多还原

【Abstract】 With the further development of fiber preparation technology,a variety of nonlinear optical fibers have been successfully prepared,prompting the continuous development of this field of nonlinear fiber optics.The regulation of nonlinear effects in optical fibers is one of the research hotspots in the field of nonlinear fiber optics in recent years.When the pulse propagates in the optical fiber,it is inevitable that it will be disturbed by higher-order linear and nonlinear effects,resulting in nonlinear phenomena such as Raman soliton self-frequency shift,third harmonic generation,four-wave mixing,and dispersion wave radiation.This nonlinear phenomena provide new perspectives for applications such as nonlinear frequency conversion,supercontinuum generation,and digital-to-analog conversion.Optical pulse shaping technology can adjust ultrashort pulses into complex waveforms to meet actual needs.The spectral phase modulation method can adjust the time domain waveform of the pulse without affecting the spectral distribution,which provides new possibilities for adjusting and controlling the nonlinear effects in the fiber.In this paper,the nonlinear phase effects in the optical fiber are investigated by spectral phase modulation of the initial input pulse,numerical simulation and theoretical analysis.First,we studied the influence of the Raman scattering effect in the fiber on the interaction between Airy pulse and the soliton.We found that Airy-solitons will fuse together after interaction,and the position of the fusion point can be controlled by changing Airy tailing direction.This control allows us to generate Airy solitons with different decelerations.Unlike the interaction between the two solitons,when the current edge soliton is replaced by an accelerated Airy pulse,the Raman-induced soliton self-frequency shift is significantly enhanced,while the decelerated Airy pulse is slightly suppressed.These characteristics are attributed to the adjustable oscillation direction of the tail of the asymmetric Airy pulse.We clearly reveal these processes through cross-correlation frequency resolution gate technology.We also studied the effect of the chirp on the Raman-induced soliton self-frequency shift when the Airy pulse contains an initial chirp.Our results not only provide a new method for manipulating the Raman-induced soliton self-frequency shift,but may also help to improve the control of soliton fusion events during the generation of supercontinuum,as well as optical strange waves and giant dispersion waves.Subsequently,we studied the law of the spectral phase modulation shaping pulse to study the dispersion wave.We found that the dispersion wave excited when the pulse is transmitted in the optical fiber can be controlled by adjusting the spectral phase of the initial input pulse.At the same time,using the tunable asymmetric oscillation pulses obtained by the second-and third-order spectral phase modulation,we realized a multiple excitation process,which greatly increased the energy of the dispersive wave.In the continuous collision between multiple peaks of an asymmetric pulse and a soliton,we give the dispersion wave frequency derived by the corresponding phase matching conditions,and we can find that the theoretical and numerical experiments are in good agreement.Our results provide a new method for controlling the dispersion wave emission in optical fibers,which may be a new strategy for developing new light sources(broadband supercontinuum generation or infrared frequency comb)for spectroscopy applications.更多还原