基于全正常色散的超短脉冲锁模光纤激光器的理论研究
发布时间：2018-10-26 12:03
【摘要】：超短激光脉冲光谱宽、脉冲宽度窄及高峰值功率等一系列显著优点使其有很高的研究和应用价值,目前,超短激光脉冲已经在微加工、医疗、通信、微观探测等许多领域取得了广泛应用。相比固体激光器,光纤激光器成本低、结构紧凑并且有很好的散热效果。工作在反常色散区的被动锁模激光器能够实现稳定的锁模脉冲输出,但光纤中积累的非线性相移限制了脉冲能量,使得传统的孤子锁模光纤激光器脉冲能量降低,提高脉冲功率会导致脉冲分裂现象。提高脉冲能量的有效方法是让激光器工作在正常色散区,通过对脉冲进行展宽来降低峰值功率,从而达到减小非线性相移的目的。本文主要研究工作在正常色散区的被动锁模光纤激光器,具体工作如下:首先,为比较工作在正常色散区和反常色散区的被动锁模光纤激光器的脉冲输出特性,设计了工作在1550nm的孤子锁模光纤激光器、色散管理孤子锁模光纤激光器以及自相似脉冲锁模光纤激光器,通过数值仿真简要对比三者在脉冲宽度、脉冲能量及峰值功率等主要参数方面的差异。数值结果得出工作在正常色散区的自相似脉冲锁模激光器的确有利于获得较高能量的脉冲。其次,本文设计了工作在1060nm的全正常色散掺镱锁模光纤激光器,详细分析了激光器脉冲输出特性。研究了色散、非线性、小信号增益系数及腔长等参数对输出脉冲宽度、脉冲能量、峰值功率的影响。最后,针对正常色散锁模光纤激光器,由于滤波器在脉冲演变过程中起到关键作用,因此有必要研究滤波器对脉冲输出特性的影响。在谐振腔内分别引入带通高斯滤波器和双折射滤波器后,通过数值仿真讨论了初始值是噪声和平滑脉冲两种情况下的脉冲输出特性。进一步改进谐振腔结构及优化腔内参数以实现稳定的锁模脉冲输出。
[Abstract]:Ultrashort laser pulse has a series of remarkable advantages, such as wide spectrum, narrow pulse width and high peak power, so it has high research and application value. At present, ultrashort laser pulse has been used in microprocessing, medical treatment, communication, etc. Micro-detection and many other fields have been widely used. Compared with solid state laser, fiber laser has the advantages of low cost, compact structure and good heat dissipation. Passive mode-locked laser operating in anomalous dispersion region can achieve stable mode-locked pulse output, but the accumulation of nonlinear phase shift in the fiber limits the pulse energy, which reduces the pulse energy of the traditional soliton mode-locked fiber laser. Increasing pulse power will lead to pulse splitting. The effective way to improve the pulse energy is to make the laser work in the normal dispersion region and reduce the peak power by broadening the pulse to reduce the nonlinear phase shift. In this paper, passive mode-locked fiber lasers working in normal dispersion region are studied. The main works are as follows: firstly, in order to compare the pulse output characteristics of passive mode-locked fiber lasers working in normal dispersion region and anomalous dispersion region, A soliton mode-locked fiber laser operating in 1550nm, a dispersion managed soliton mode-locked fiber laser and a self-similar pulse mode-locked fiber laser are designed. The difference of main parameters such as pulse energy and peak power. The numerical results show that the self-similar pulse mode-locked laser operating in the normal dispersion region is indeed beneficial to obtain higher energy pulses. Secondly, a fully normal dispersion mode-locked ytterbium-doped fiber laser working in 1060nm is designed, and the pulse output characteristics of the laser are analyzed in detail. The effects of parameters such as dispersion, nonlinearity, small signal gain coefficient and cavity length on the output pulse width, pulse energy and peak power are studied. Finally, for the normal dispersion mode-locked fiber laser, the filter plays a key role in the pulse evolution, so it is necessary to study the influence of the filter on the pulse output characteristics. After introducing band-pass Gao Si filter and birefringent filter into the resonator, the pulse output characteristics with initial value of noise and smooth pulse are discussed by numerical simulation. The structure of the cavity is further improved and the parameters in the cavity are optimized to realize the stable output of the mode-locked pulse.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
本文编号：2295655
[Abstract]:Ultrashort laser pulse has a series of remarkable advantages, such as wide spectrum, narrow pulse width and high peak power, so it has high research and application value. At present, ultrashort laser pulse has been used in microprocessing, medical treatment, communication, etc. Micro-detection and many other fields have been widely used. Compared with solid state laser, fiber laser has the advantages of low cost, compact structure and good heat dissipation. Passive mode-locked laser operating in anomalous dispersion region can achieve stable mode-locked pulse output, but the accumulation of nonlinear phase shift in the fiber limits the pulse energy, which reduces the pulse energy of the traditional soliton mode-locked fiber laser. Increasing pulse power will lead to pulse splitting. The effective way to improve the pulse energy is to make the laser work in the normal dispersion region and reduce the peak power by broadening the pulse to reduce the nonlinear phase shift. In this paper, passive mode-locked fiber lasers working in normal dispersion region are studied. The main works are as follows: firstly, in order to compare the pulse output characteristics of passive mode-locked fiber lasers working in normal dispersion region and anomalous dispersion region, A soliton mode-locked fiber laser operating in 1550nm, a dispersion managed soliton mode-locked fiber laser and a self-similar pulse mode-locked fiber laser are designed. The difference of main parameters such as pulse energy and peak power. The numerical results show that the self-similar pulse mode-locked laser operating in the normal dispersion region is indeed beneficial to obtain higher energy pulses. Secondly, a fully normal dispersion mode-locked ytterbium-doped fiber laser working in 1060nm is designed, and the pulse output characteristics of the laser are analyzed in detail. The effects of parameters such as dispersion, nonlinearity, small signal gain coefficient and cavity length on the output pulse width, pulse energy and peak power are studied. Finally, for the normal dispersion mode-locked fiber laser, the filter plays a key role in the pulse evolution, so it is necessary to study the influence of the filter on the pulse output characteristics. After introducing band-pass Gao Si filter and birefringent filter into the resonator, the pulse output characteristics with initial value of noise and smooth pulse are discussed by numerical simulation. The structure of the cavity is further improved and the parameters in the cavity are optimized to realize the stable output of the mode-locked pulse.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248
【引证文献】
相关硕士学位论文 前1条
1 王文权;多芯光纤可饱和吸收体的数值研究[D];北京交通大学;2017年
，本文编号：2295655
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