【摘要】：超短激光脈沖光譜寬、脈沖寬度窄及高峰值功率等一系列顯著優(yōu)點使其有很高的研究和應用價值,目前,超短激光脈沖已經在微加工、醫(yī)療、通信、微觀探測等許多領域取得了廣泛應用。相比固體激光器,光纖激光器成本低、結構緊湊并且有很好的散熱效果。工作在反常色散區(qū)的被動鎖模激光器能夠實現穩(wěn)定的鎖模脈沖輸出,但光纖中積累的非線性相移限制了脈沖能量,使得傳統(tǒng)的孤子鎖模光纖激光器脈沖能量降低,提高脈沖功率會導致脈沖分裂現象。提高脈沖能量的有效方法是讓激光器工作在正常色散區(qū),通過對脈沖進行展寬來降低峰值功率,從而達到減小非線性相移的目的。本文主要研究工作在正常色散區(qū)的被動鎖模光纖激光器,具體工作如下:首先,為比較工作在正常色散區(qū)和反常色散區(qū)的被動鎖模光纖激光器的脈沖輸出特性,設計了工作在1550nm的孤子鎖模光纖激光器、色散管理孤子鎖模光纖激光器以及自相似脈沖鎖模光纖激光器,通過數值仿真簡要對比三者在脈沖寬度、脈沖能量及峰值功率等主要參數方面的差異。數值結果得出工作在正常色散區(qū)的自相似脈沖鎖模激光器的確有利于獲得較高能量的脈沖。其次,本文設計了工作在1060nm的全正常色散摻鐿鎖模光纖激光器,詳細分析了激光器脈沖輸出特性。研究了色散、非線性、小信號增益系數及腔長等參數對輸出脈沖寬度、脈沖能量、峰值功率的影響。最后,針對正常色散鎖模光纖激光器,由于濾波器在脈沖演變過程中起到關鍵作用,因此有必要研究濾波器對脈沖輸出特性的影響。在諧振腔內分別引入帶通高斯濾波器和雙折射濾波器后,通過數值仿真討論了初始值是噪聲和平滑脈沖兩種情況下的脈沖輸出特性。進一步改進諧振腔結構及優(yōu)化腔內參數以實現穩(wěn)定的鎖模脈沖輸出。
[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.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN248

【引證文獻】

相關碩士學位論文 前1條

1 王文權;多芯光纖可飽和吸收體的數值研究[D];北京交通大學;2017年

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本文編號：2295655