基于磁流体可饱和吸收体掺铒光纤激光器研究

发布时间：2018-03-24 09:32

本文选题：调Q　切入点：磁流体可饱和吸收体　出处：《深圳大学》2017年硕士论文

【摘要】：脉冲激光器在光纤通信、医疗器械仪器设备、大型基础设施、军事国防安全、激光打标、激光切割等方面有着广泛的应用。其具有结构紧凑、光束和光脉冲质量较好等优点。与主动调Q相比,被动调Q具有结构紧凑、易于实现全光纤化、成本相对低廉、操作简化等优势,而且可以获得更短的脉冲,获得得更大的重复频率。在被动调Q光纤激光器中,最为关键的是具有可饱和吸收效应的材料及器件的开发与应用。由于传统的可饱和吸收体(如半导体可饱和吸收镜等)存在制作工艺复杂、价格昂贵等缺陷,限制了脉冲激光器的发展,推动了研究人员对新材料的探索。随后新型的纳米材料(如碳纳米管、石墨烯、拓扑绝缘体、过渡金属硫化物、磁流体等)不断涌现,这些新材料具有各自独特的光学与电子学性质,成为当下的研究热点。最近,新型纳米功能性材料磁流体也引起了研究人员的关注,磁流体纳米颗粒由于其有限的尺寸以及表面效应具有大的光学非线性以及较大的弛豫时间等,使其在脉冲激光器方面具有广泛的应用前景。本论文利用磁流体可饱和吸收体,在掺铒光纤激光器中实现不同被动调Q的运转。本论文的主要工作如下:1.简单介绍了脉冲光纤激光器的应用及脉冲激光器相对传统固体激光器的优点、被动调Q光纤激光器相对于主动调Q的优势、采用不同被动调Q技术光纤激光器的分类及其优点。以及介绍基于可饱和吸收体的调Q光纤激光器的研究进展。2.简述了调Q原理,对磁流体做简要介绍并分析了磁流体可饱和吸收体原理。接着对磁流体材料表征以及测量其线性透过率,1560nm处薄膜的线性吸收为32.8%。,并对实验所用的磁流体材料进行拉曼测试,磁流体的三个特征峰分别位于284cm~(-1)、490cm~(-1)和695cm~(-1)。最后对吸收体进行非线性光学特性的表征,测量得出可饱和吸收曲线,磁流体的饱和光强约为98.15MW/cm2,非线性损耗约为19.83%,调制深度为11.03%。3.基于磁流体的单波长调Q掺铒光纤激光器实验:运用旋涂法将磁流体溶液旋涂在光纤连接头之间,并通过法兰盘固定以制备三明治型可饱和吸收体,在掺铒光纤激光器中实现调Q输出。测得的调Q脉冲信噪比为54.4dB,光谱的中心波长在1558.4nm附近,3dB带宽约为1.8nm。当泵浦功率为550mW时,实验获得的最大的平均输出功率为41.2mW,最大的单脉冲能量为321.3nJ。4.基于磁流体多波长调Q掺铒光纤激光器:简单介绍多波长激光器的特点以及实现多波长激光器的几种方法。本实验主要是通过在腔内加入马赫曾德干涉装置,并以磁流体作为可饱和吸收体器件,搭建一套多波长掺铒光纤环形激光器,实验结果中光纤激光器实现了调Q锁模,获得了18个波长同时输出。随后对制作的可饱和吸收体器件的调Q特性进行表征。该光纤激光器在泵浦功率从30mW增加到340mW时,输出脉冲的重复频率从9.83kHz增加到53.24 kHz,单脉冲能量从8.32nJ增加到117.62nJ,而脉冲宽度从3.9μs减小到1.01μs。5.基于磁流体的可调谐调Q掺铒光纤激光器实验:加入磁流体SA,在掺铒光纤激光器中以获得稳定调Q脉冲;在此基础上在腔内加入可调滤波器,实现了波长可调谐的调Q脉冲输出,固定泵浦功率,得到1513.14nm~(-1)564.70nm之间连续可调,调谐范围为~52nm。脉冲信噪比为46dB,激光器具有较好的稳定性。
[Abstract]:Pulse laser in the optical fiber communication equipment, medical equipment, large-scale infrastructure, military defense, laser marking, laser cutting has been widely used and so on. It has the advantages of compact structure, light pulse of light and good quality. Compared with the active Q and passive Q has the advantages of compact structure, easy to realize all fiber, relatively low cost, simple operation and other advantages, and can obtain shorter pulse repetition frequency, gain greater. In passively Q fiber laser, the most critical is the development and application of saturable absorption effect of the materials and devices. Because the traditional (such as semiconductor saturable absorber saturable absorption mirror) existing production process is complex, expensive cost, restrict the development of pulsed lasers, promoted the exploration of new materials researchers. Then the new nanometer material (such as carbon nanotubes and graphite Graphene, topological insulator, transition metal sulfides, magnetic fluid, etc.) are constantly emerging, these new materials have their unique optical and electronic properties, has become a research hotspot. Recently, new nano functional materials, magnetic fluid has attracted the attention of researchers, magnetic fluid nanoparticles due to their limited size and surface effect large optical nonlinearity and large relaxation time, which has wide application prospect in the aspects of pulse laser. This paper using magnetic fluid absorber, in erbium-doped fiber laser passively Q realize different operation. The main work of this paper are as follows: 1. introduces the advantages of the application of pulse fiber laser and compared with the traditional solid laser pulse laser, passively Q-switched fiber laser in Q compared to the active Q advantage, using different passive Q optical fiber laser technology The classification and its advantages. And introduces the research progress of.2. Q fiber laser with a saturable absorber is briefly introduced. Based on the principle of Q, makes a brief introduction of the magnetic fluid and the analysis of the magnetic fluid saturable absorber principle. Then to characterize the magnetic fluid material and measuring the linear transmittance of linear 1560nm thin film absorption of 32.8%., magnetic the fluid material and the experimental use of Raman test, three peaks of the magnetic fluid are located at 284cm~ (-1), 490cm~ (-1) and 695cm~ (-1). The characterization of nonlinear optical properties of the absorber, measured by saturable absorption curve, the saturation intensity of the magnetic fluid is about 98.15MW/cm2, nonlinear the loss is about 19.83%, the modulation depth of 11.03%.3. magnetic fluid Q single wavelength erbium doped fiber laser based on experiment: using spin coating method, magnetic fluid solution spin coating on the optical fiber connector, and fixed by the flange To prepare a sandwich type saturable absorber, the output of Q in erbium-doped fiber laser. The measured Q pulse signal to noise ratio is 54.4dB, the central wavelength spectrum in the vicinity of 1558.4nm, 3dB bandwidth is about 1.8nm. when the pump power is 550mW, the maximum average output power is 41.2mW, maximum the single pulse energy of 321.3nJ.4. magnetic fluid multi wavelength erbium doped fiber laser based on Q: a brief introduction of characteristics of multi wavelength laser and several methods of multi wavelength laser. The experiment was used to Maher Ceng De interferometer and using the magnetic fluid as the saturable absorber device, build a set of multi wavelength erbium doped fiber ring laser, experimental results in fiber laser Q switched mode-locked, obtained 18 wavelength output at the same time. Then the characterization of Q production characteristics of saturable absorber of the optical device. The fiber laser was increased from 30mW to 340mW at the pump power, pulse repetition frequency is increased from 9.83kHz to 53.24 kHz, single pulse energy is increased from 8.32nJ to 117.62nJ, and a pulse width from 3.9 s reduced to 1.01 s.5. based on the magnetic fluid can be tunable erbium-doped fiber laser Q experiment: adding magnetic fluid SA and in the erbium-doped fiber laser to obtain stable Q pulse; on the basis of the manual tunable filter, the Q pulse output wavelength tunable, fixed pump power, 1513.14nm~ (-1) 564.70nm continuously adjustable tuning range of SNR is 46dB ~52nm. pulse laser has better stability.

【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

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