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题名	1.2μm波段脉冲光纤激光器研究
作者	杨学宗
学位类别	硕士
答辩日期	2016
授予单位	中国科学院上海光学精密机械研究所
导师	冯衍
关键词	光纤激光器 受激拉曼散射 钬掺杂ZBLAN光纤 锁模 调Q
其他题名	Research on pulsed fiber lasers at 1.2 μm
中文摘要	1.2μm波段的脉冲激光在激光医疗美容、光谱学、先进成像技术、天文学检测、非线性光学显微镜等领域应用广泛。光纤脉冲激光器相比固体、染料、气体等脉冲激光器具有结构紧凑、耐用性高、设计灵活、光束质量好等优点，更受人们的青睐。因此，1.2μm波段脉冲光纤激光器在科学研究和现实生活中具有良好的发展前景。但是，在1.2μm波段传统的光纤增益介质很少（掺镱离子光纤、掺铋光纤），而且存在的限制比较多，比如效率低、增益竞争严重，因此在该波段得到高效的光纤激光一直是人们研究的热点。近些年来，基于受激拉曼散射原理的拉曼光纤激光器和基于Ho3+掺杂的ZBLAN光纤（增益介质）的光纤激光器在该波段表现出较强进的优势和较高的效率，受到研究者的广泛关注。我们基于这两种增益机制和有效的锁模、调Q脉冲技术，研究了1178nm主动锁模拉曼光纤激光器，1193nm钬掺杂ZBLAN光纤锁模激光器，和1.2μm波长灵活的钬掺杂ZBLAN光纤调Q激光器。论文的主要研究内容包括： 第一章主要介绍了1.2μm波段激光的应用和研究现状以及光纤激光器的发展优势；介绍了1.2μm波段光纤激光器中的多种增益机制；介绍了1.2μm波段脉冲光纤激光器的重要地位及发展前景以及脉冲光纤激光器的调Q和锁模的原理及方法。 第二章主要介绍1178nm主动锁模拉曼光纤激光器的研究，该研究是主动方式锁模的拉曼光纤激光器的首次报道。全保偏光纤组成的光纤环形腔总长约为500m，由1120 nm线偏振的掺Yb3+光纤激光器作为泵浦源，声光调制器作为主动调节机制。通过调节声光调制器的打开时间和调制频率，实现了2 ns宽的1178 nm的稳定锁模脉冲。在更高泵浦功率时，锁模脉冲展宽，观察到2阶拉曼-斯托克斯光的产生，并且通过调节声光调制器的打开时间和调制频率可以有效抑制2阶拉曼-斯托克斯光。对主动锁模脉冲建立过程的研究，证实了拉曼激光器中不存在驰豫振荡过程。另外，通过调节声光调制器的重复频率，实现了392 kHz到31.37 MHz的谐波锁模。 第三章主要介绍1193nm钬掺杂ZBLAN光纤锁模激光器的研究，该光纤激光器是基于钬掺杂ZBLAN光纤在1.2μm波段的首次锁模报道，锁模机制是非线性偏振旋转锁模技术。激光器的泵浦源是1137nm的拉曼光纤激光器。腔内引入Lyot滤波器，它由一段保偏光纤和一个偏振相关的光学隔离器构成，得到脉宽47ps、能量1.3nJ、重复频率1.77MHz的稳定耗散孤子锁模脉冲。在更高泵浦功率下，实现脉冲簇锁模运转，脉冲簇能量高达6.7nJ。 第四章主要包含1.2μm波长灵活的钬掺杂ZBLAN光纤调Q激光器的实验研究。1137nm拉曼光纤激光器作为泵浦源泵浦钬掺杂ZBLAN增益光纤，非线性偏振旋转技术作为可饱和吸收体提供幅度调制。腔内引入Lyot滤波器，调节腔内振荡波长，得到脉宽0.7μs、脉冲能量0.5 μJ的稳定调Q脉冲。另外利用Lyot滤波器周期性的透射特性实现了1190-1196nm波长可调谐和双波长调Q脉冲。
英文摘要	Pulse lasers operating in the 1.2 μm region have found a variety of applications in laser medical cosmetology, spectroscopy, advanced imaging technology, astronomy detection, nonlinear optical microscope, etc. Compared with solid, dye, gas and other pulse laser, fiber pulse laser has the advantages of compact structure, high robustness, flexible design, good beam quality, etc. Therefore, 1.2μm pulse fiber laser has a good development prospect in scientific research and real life. But, there are very few kinds of fiber gain medium in 1.2μm. Yb3+-doped and Bi-doped silica fiber with strong gain competitive effect or low emission efficiency cannot up to the requirements of 1.2μm fiber laser. Therefore, researches of high efficiency fiber gain media in this emission band have always been a hot topic. In recent years, Raman fiber laser based on stimulated Raman scattering and fiber laser based on Ho3+-doped ZBLAN fiber have been widely concerned, due to their high efficiency and other advantages in 1.2μm. Using these two gain mechanisms and effective mode locking, Q switching technology, we have realized an active mode-locking of Raman fiber laser at 1178nm; a mode-locked Ho3+-doped ZBLAN fiber laser at 1193 nm; a wavelength-flexible Q-switched Ho3+-doped ZBLAN fiber laser at 1.2 μm. In Chapter I, we mainly introduce the application and research status of 1.2 μm laser and the advantages of fiber laser compared to other kinds of lasers. Multiple fiber gain mechanisms in 1.2 μm are introduced. Important status and developing prospect of the 1.2 μm pulse fiber laser and corresponding mode locking and Q switching technology are introduced. In Chapter II, active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~ 500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking. In Chapter III, a mode-locked Ho3+-doped ZBLAN fiber laser at 1.2 μm was demonstrated for the first time employing a nonlinear polarization rotation technique for mode-locking. The laser was pumped at 1137 nm by a Raman fiber laser. Stable dissipative soliton mode-locking was achieved with an intra-cavity Lyot filter formed from a length of polarization maintaining fiber and a polarization dependent optical isolator. 1.3-nJ pulses with pulse duration of 47 ps at a repetition rate of 1.77 MHz were produced. Multiple pulse operation with burst energy up to 6.7 nJ was observed at higher pump power. In Chapter IV, wavelength-flexible Q-switched Ho3+-doped ZBLAN fiber laser at 1.2 μm is experimentally investigated. The gain medium is Ho3+-doped ZBLAN fiber, which is pumped by an 1137 nm Raman fiber laser. Nonlinear polarization rotation technique worked as the saturable absorber is adopted in the ring cavity to provide the amplitude modulation. An artifical Loyt filter is inserted into the cavity. Stable Q-Switched pulse trains with the pulse duration 0.7 μs and pulse energy 0.5 μJ are achieved. The periodic transmission spectrum of Lyot filter allows for the laser operating in tunable wavelengths from 1190 to 1196 nm and dual-wavelength Q-switched pulses are observed.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16975]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	杨学宗. 1.2μm波段脉冲光纤激光器研究[D]. 中国科学院上海光学精密机械研究所. 2016.

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