本文選題：調Q　切入點：磁流體可飽和吸收體　出處：《深圳大學》2017年碩士論文

【摘要】：脈沖激光器在光纖通信、醫(yī)療器械儀器設備、大型基礎設施、軍事國防安全、激光打標、激光切割等方面有著廣泛的應用。其具有結構緊湊、光束和光脈沖質量較好等優(yōu)點。與主動調Q相比,被動調Q具有結構緊湊、易于實現(xiàn)全光纖化、成本相對低廉、操作簡化等優(yōu)勢,而且可以獲得更短的脈沖,獲得得更大的重復頻率。在被動調Q光纖激光器中,最為關鍵的是具有可飽和吸收效應的材料及器件的開發(fā)與應用。由于傳統(tǒng)的可飽和吸收體(如半導體可飽和吸收鏡等)存在制作工藝復雜、價格昂貴等缺陷,限制了脈沖激光器的發(fā)展,推動了研究人員對新材料的探索。隨后新型的納米材料(如碳納米管、石墨烯、拓撲絕緣體、過渡金屬硫化物、磁流體等)不斷涌現(xiàn),這些新材料具有各自獨特的光學與電子學性質,成為當下的研究熱點。最近,新型納米功能性材料磁流體也引起了研究人員的關注,磁流體納米顆粒由于其有限的尺寸以及表面效應具有大的光學非線性以及較大的弛豫時間等,使其在脈沖激光器方面具有廣泛的應用前景。本論文利用磁流體可飽和吸收體,在摻鉺光纖激光器中實現(xiàn)不同被動調Q的運轉。本論文的主要工作如下:1.簡單介紹了脈沖光纖激光器的應用及脈沖激光器相對傳統(tǒng)固體激光器的優(yōu)點、被動調Q光纖激光器相對于主動調Q的優(yōu)勢、采用不同被動調Q技術光纖激光器的分類及其優(yōu)點。以及介紹基于可飽和吸收體的調Q光纖激光器的研究進展。2.簡述了調Q原理,對磁流體做簡要介紹并分析了磁流體可飽和吸收體原理。接著對磁流體材料表征以及測量其線性透過率,1560nm處薄膜的線性吸收為32.8%。,并對實驗所用的磁流體材料進行拉曼測試,磁流體的三個特征峰分別位于284cm~(-1)、490cm~(-1)和695cm~(-1)。最后對吸收體進行非線性光學特性的表征,測量得出可飽和吸收曲線,磁流體的飽和光強約為98.15MW/cm2,非線性損耗約為19.83%,調制深度為11.03%。3.基于磁流體的單波長調Q摻鉺光纖激光器實驗:運用旋涂法將磁流體溶液旋涂在光纖連接頭之間,并通過法蘭盤固定以制備三明治型可飽和吸收體,在摻鉺光纖激光器中實現(xiàn)調Q輸出。測得的調Q脈沖信噪比為54.4dB,光譜的中心波長在1558.4nm附近,3dB帶寬約為1.8nm。當泵浦功率為550mW時,實驗獲得的最大的平均輸出功率為41.2mW,最大的單脈沖能量為321.3nJ。4.基于磁流體多波長調Q摻鉺光纖激光器:簡單介紹多波長激光器的特點以及實現(xiàn)多波長激光器的幾種方法。本實驗主要是通過在腔內加入馬赫曾德干涉裝置,并以磁流體作為可飽和吸收體器件,搭建一套多波長摻鉺光纖環(huán)形激光器,實驗結果中光纖激光器實現(xiàn)了調Q鎖模,獲得了18個波長同時輸出。隨后對制作的可飽和吸收體器件的調Q特性進行表征。該光纖激光器在泵浦功率從30mW增加到340mW時,輸出脈沖的重復頻率從9.83kHz增加到53.24 kHz,單脈沖能量從8.32nJ增加到117.62nJ,而脈沖寬度從3.9μs減小到1.01μs。5.基于磁流體的可調諧調Q摻鉺光纖激光器實驗:加入磁流體SA,在摻鉺光纖激光器中以獲得穩(wěn)定調Q脈沖;在此基礎上在腔內加入可調濾波器,實現(xiàn)了波長可調諧的調Q脈沖輸出,固定泵浦功率,得到1513.14nm~(-1)564.70nm之間連續(xù)可調,調諧范圍為~52nm。脈沖信噪比為46dB,激光器具有較好的穩(wěn)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.

【學位授予單位】：深圳大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN248

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本文編號：1657704