本文選題：高功率 + 調(diào)Q脈沖　； 參考：《電子科技大學(xué)》2017年碩士論文

【摘要】：近年來(lái),波長(zhǎng)為3μm的高功率光纖激光器因其在激光手術(shù)、材料加工、軍事對(duì)抗以及科研等方面的巨大應(yīng)用前景,同時(shí)相比于其它類型的激光器具有光束質(zhì)量高、散熱性能好、轉(zhuǎn)換效率高、靈活性好等特點(diǎn),從而激起了海內(nèi)外科研人員極大的研究興趣。基于中紅外光纖激光器的以上特點(diǎn),本文著重研究高功率連續(xù)和調(diào)Q脈沖中紅外光纖激光器。主要內(nèi)容可以分為以下幾個(gè)部分:(1)基于高濃度摻Er~(3+)ZBLAN光纖中鉺離子的能級(jí)躍遷過(guò)程,建立了表示各能級(jí)粒子數(shù)密度變化的速率方程和表征功率隨時(shí)間和空間變化的功率傳輸方程,同時(shí)結(jié)合諧振腔邊界條件構(gòu)建了高濃度摻Er~(3+)ZBLAN光纖激光器系統(tǒng)模型。通過(guò)綜合考慮激光斜率效率、閾值泵浦功率和光纖產(chǎn)熱等隨諧振腔參數(shù)及泵浦源參數(shù)的變化,我們對(duì)光纖長(zhǎng)度、摻雜濃度、輸出反射率和泵浦波長(zhǎng)等因素進(jìn)行了優(yōu)化。(2)利用4.1m長(zhǎng)的高濃度摻Er~(3+)ZBLAN光纖作為增益光纖,搭建了高功率摻Er~(3+)ZBLAN光纖激光器,并研究了其輸出特性。最終,實(shí)現(xiàn)了最大功率為7.11W,中心波長(zhǎng)為2802nm的連續(xù)激光輸出,對(duì)應(yīng)最大功率波動(dòng)范圍為4.3%,斜率效率為36.06%,已經(jīng)超過(guò)34.3%的斯托克斯極限。(3)首先,我們搭建了基于SESAM可飽和吸收體的被動(dòng)調(diào)Q摻Er~(3+)ZBLAN光纖激光器,并得到了穩(wěn)定的調(diào)Q脈沖。研究分析了對(duì)應(yīng)不同泵浦功率的調(diào)Q脈沖輸出特性,得到了最大脈沖能量為3.52μJ,平均功率為0.252W,脈寬為1.7μs,重復(fù)頻率為71.43kHz,中心波長(zhǎng)為2786.8nm的穩(wěn)定調(diào)Q脈沖激光。而后,我們搭建了基于高濃度摻Er~(3+)ZBLAN光纖的主振蕩功率放大(Master Oscillator Power Amplifier,簡(jiǎn)稱MOPA)系統(tǒng),將前面得到的穩(wěn)定調(diào)Q脈沖作為種子源注入MOPA系統(tǒng),研究了MOPA系統(tǒng)中不同光纖端面切角下輸出脈沖的放大特性,最終得到了最大平均功率和脈沖能量分別為4.2W和58.87μJ的放大脈沖輸出,對(duì)應(yīng)脈沖寬度為2.29μs,重復(fù)頻率為71.73kHz,光譜的中心波長(zhǎng)為2786.8nm,MOPA系統(tǒng)的斜率效率為30.79%。
[Abstract]:In recent years, high power fiber lasers with wavelength of 3 渭 m have great application prospects in laser surgery, material processing, military confrontation and scientific research, at the same time, compared with other types of lasers, they have high beam quality and good heat dissipation performance. The characteristics of high conversion efficiency and good flexibility have aroused great interest of researchers at home and abroad. Based on the above characteristics of mid-infrared fiber laser, this paper focuses on the study of high power CW and Q-switched pulse mid-infrared fiber laser. The main contents can be divided into the following parts: 1) based on the energy level transition process of erbium ion in high concentration doped Er~(3 fiber, The rate equation representing the change of particle number density of each energy level and the power transmission equation representing the change of power with time and space are established. The system model of high concentration Er~(3 doped ZBLAN-based fiber laser is constructed in combination with the resonator boundary condition. By considering the variation of laser slope efficiency, threshold pump power and optical fiber heat production with the parameters of resonator and pump source, the length of fiber and the concentration of doped fiber are studied. The output reflectivity and pump wavelength were optimized. (2) High power Er~(3 doped ZBLAN-based fiber laser was constructed using 4.1m long high concentration Er~(3 doped ZBLAN-based fiber as gain fiber, and its output characteristics were studied. Finally, a continuous laser output with a maximum power of 7.11W and a center wavelength of 2802nm is achieved, corresponding to the maximum power fluctuation range of 4.3, the slope efficiency of 36.06, which has exceeded the Stokes limit of 34.3%. A passive Q-switched Er~(3 doped ZBLAN-based fiber laser based on SESAM saturable absorber is constructed and stable Q-switched pulses are obtained. The characteristics of Q-switched pulse with different pump power are studied and analyzed. A stable Q-switched laser with maximum pulse energy of 3.52 渭 J, average power of 0.252 W, pulse width of 1.7 渭 s, repetition rate of 71.43 kHz and center wavelength of 2786.8nm is obtained. Then, a master power amplifier master Oscillator Power Amplifier, system based on high concentration Er~(3 doped ZBLAN fiber is built, and the stable Q-switched pulse is injected into the MOPA system as a seed source. The amplification characteristics of output pulses at different fiber end tangent angles in MOPA system are studied. The maximum average power and pulse energy are 4.2W and 58.87 渭 J, respectively. The corresponding pulse width is 2.29 渭 s, the repetition rate is 71.73 kHz, and the central wavelength of the spectrum is 2786.8 nm. The slope efficiency of MOPA system is 30.79.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN248

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