共查询到20条相似文献,搜索用时 15 毫秒
1.
We derive a theoretical model to characterize the mode-locking dynamics in a single-mode fiber laser cavity with a combination
of waveplates and a passive polarizer. The averaging process results in the cubic-quintic Ginzburg-Landau equation (CQGLE)
where all the coefficients depend explicitly on the setting of the waveplates as well as the fiber birefringence. A comparison
between full numerical simulations and the CQGLE shows a good agreement that allows for characterizing the stability and operating
regimes of the laser cavity. A low-dimensional model is developed via the method of proper orthogonal decomposition (POD)
to study the multi-pulsing transition of the CQGLE, and the results agree qulitatively with the CQGLE model. The theory allows
one to develop guidelines for engineering and optimizing high-energy, high peak-power pulses in the laser cavity. 相似文献
2.
Wang L. Y. Xu W. C. Luo Z. C. Cao W. J. Luo A. P. Dong J. L. Wang H. Y. 《Laser Physics》2011,21(10):1808-1812
We experimentally demonstrate a passively Q-switched mode-locking (QML) operation in an Erbium-doped fiber ring laser with
net normal dispersion by using nonlinear polarization rotation technique. A 2 m long section of dispersion compensating fiber
(DCF) with extra large positive dispersion was inserted into the cavity to ensure the fiber laser working in the region of
net positive dispersion. By carefully adjusting the polarization controller, both uniform dissipative mode-locking pulses
with fundamental repetition rate and QML pulse trains with tunable repetition rate from 71.58 to 98.83 kHz are achieved. It
is found that the QML operation is caused by the interaction between the polarization state of the pulse and the intracavity
polarizer. 相似文献
3.
实验研究了基于掺Yb偏振型大模场面积光子晶体光纤的孤子锁模激光器,获得了高脉冲能量的飞秒激光输出. 激光器基于线形腔结构,利用光栅对补偿腔内色散,并通过半导体可饱和吸收镜实现锁模的自启动. 实验中从振荡级直接获得了平均功率为700mW, 重复频率为47.3MHz(对应于14.8 nJ的单脉冲能量),脉冲宽度为518 fs的稳定锁模脉冲输出. 与普通孤子锁模飞秒光纤激光器相比,输出的单脉冲能量提高了两个数量级.
关键词:
光子晶体光纤
飞秒
光纤激光器
孤子锁模 相似文献
4.
We experimentally demonstrate an all-normal-dispersion Yb-doped mode-locked fibre laser with no intentional spectral filter inserted.Pulses with 1.1 nJ pulse energy at a repetition rate of 20.4 MHz are achieved.A theoretical model of the fibre laser is derived,whose coefficients are explicitly dependent on the orientations of the wave plates and the polarizer.Based on the model,stability diagrams of both the mode-locking and the continuous wave regimes of the laser are presented.The influence of group-velocity dispersion (GVD) and cavity length on the stability of mode-locking is also discussed. 相似文献
5.
6.
Xiaoyang Guo Yi Xu Yanyan Li Xiao Zou Xiaoming Lu Cheng Wang Yuxin Leng Ruxin Li 《Applied physics. B, Lasers and optics》2014,117(3):973-978
A high-temporal contrast femtosecond Stokes pulse near 1,053 nm is obtained simply without polarizer extinction ratio limitation based on the stimulated Raman frequency shift process in ethanol with an 800-nm femtosecond Ti:sapphire laser as a pump source. By optimizing the incident pump pulse chirp and the ethanol Raman cell length, a clean Stokes pulse near 1,053 nm with a maximum energy of 0.24 mJ is obtained with ~7.5 % conversion efficiency and 0.8 % (rms) energy fluctuation. Compared with the incident pump pulse, the temporal contrast of the Stokes pulse is improved by at least approximately three orders of magnitude. 相似文献
7.
《中国光学快报(英文版)》2016,(4)
In this Letter, a simple and passively mode-locking Yb-doped all fiber laser using a nonlinear polarization rotation technique operating under dissipative soliton(DS) or dissipative soliton resonance(DSR) conditions is proposed, furthermore, using a combination of a bandpass filter and a Loyt filter, tunable single-wavelength or dual-wavelength operation under two different conditions is realized, respectively. The tunable single?wavelength DS laser has a 5 nm tuning range from 1029 to 1034 nm with a pulse width of 110 ps. The tunable single-wavelength DSR operation laser has a range of 4 nm. In-depth research on the mechanism of the con?version between DS and DSR is carried out. Particularly, under dual-wavelength DSR operation, the obtained step-like pulses consist of two rectangular pulses with different energies. This work could help give a deeper insight into normal dispersion pulses. 相似文献
8.
The theory of active-passive mode-locked solid-state lasers is developed where the passive mode-locking is achieved by a nonlinear mirror. Steady-state cw numerical solutions are analyzed in detail for the case of a Nd: YAG laser. The steady-state pulse duration can be reduced by an order of magnitude as compared to the pure active mode-locking regime.On leave from Department of Quantum Electronics, Faculty of Physics, University of Sofia, BG-1126 Sofia, Bulgaria 相似文献
9.
Multi-operation state in an all-normal-dispersion ytterbium-doped fiber laser is obtained by introducing nonlinear polarization
or hybrid mode-locking mechanism in the laser cavity. In addition to operating the laser at continuous-wave mode-locking,
various operation states including continuous-wave, Q-switched mode-locking, pulse-splitting, and harmonic mode-locking can
be achieved by tuning the laser pump power or an intracavity polarization controller. Insertion of a semiconductor saturable
absorber mirror in the cavity helps to shorten the output pulsewidth of the hybrid mode-locked laser. When the pump power
is rapidly adjusted, a strong asymmetric hysteresis behavior can be observed during the manipulation between different orders
of harmonic mode-locking. 相似文献
10.
Robins NP Figl C Haine SA Morrison AK Jeppesen M Hope JJ Close JD 《Physical review letters》2006,96(14):140403
In this Letter we present experimental results and a simple analytic theory on the first continuous (long pulse) Raman atom laser. We analyze the flux and brightness of a generic two state atom laser with an analytic model that shows excellent agreement with our experiments. We show that, for the same source size, the brightness achievable with a Raman atom laser is at least 3 orders of magnitude greater than achievable in any other demonstrated continuously outcoupled atom laser. 相似文献
11.
建立理论模型,讨论了非线性偏振旋转全光纤锁模激光器的锁模过程、谐波过程以及导致激光器锁模运行难以稳定的影响因素.讨论了采用啁啾脉冲光谱滤波产生脉冲自振幅调制、增加激光器锁模稳定性和自启动能力的机理以及非线性偏振旋转与啁啾脉冲光谱滤波相结合实现锁模的物理过程和脉冲演化过程.研制出全光纤结构的超短脉冲掺Yb~(3+)光纤环形激光器,采用非线性偏振旋转和啁啾脉冲光谱滤波相结合的锁模技术,实现了激光器锁模的开机自启动和高稳定运行.对激光器进行了长期运行稳定性、锁模开机自启动能力、锁模输出参数可重复性监测.锁模脉冲中心波长1052.9 nm,谱宽9.1 nm,脉冲能量4.25 nJ,脉冲宽度17.8 ps.运行期间,各参数波动均小于0.3%.开机自启动能力和可重复性测试显示,激光器可实现一键自启动,启动后各参数可重复精度在0.55%以内. 相似文献
12.
Fei Ai Zhigang Cao Xifen Zhang Chengmei Zhang Bo Zhang Benli Yu 《Optics & Laser Technology》2011,43(3):501-505
We propose and demonstrate a strictly all-fiber, erbium doped passively mode-locked figure-eight fiber laser (EDFL). In the laser structure, we use the nonlinear optical loop mirror combination with a variable ratio coupler (VRC-NOLM) to achieve mode-locking. Due to the nonlinear effect in the nonlinear fiber, stable self-starting pulse is obtained. In order to reduce the repetition of pulse, a segment of nonlinear fiber (NLF) has been incorporated into the VRC-NOLM. The laser generates stable rectangular pulses with a low repetition rate (kilohertz magnitude) by extending the length of the cavity. Furthermore, the output pulse width of the fiber laser can be varied by changing the coupler ratio of the variable ratio coupler. 相似文献
13.
采用常规透镜设计了适用于非真空环境中交叉偏振波(XPW)产生的双透镜聚焦系统,在相对较短的距离实现了长焦透镜聚焦的效果,并测量了聚焦后的激光脉冲,发现其没有显著的非线性相位积累,保证了激光光束质量.在非真空中采用双BaF_2晶体得到了XPW系统转换效率22%,光谱1.78倍展宽的净化脉冲输出,双透镜组合聚焦形式使得双BaF_2晶体间距在13—22 cm内可保证20%以上的XPW转换效率,双晶体间距的调节冗余度提高了两个量级,极大地降低了双晶转换效率对晶体间距的依赖.这种正负透镜组合聚焦的光路设计在非真空中实现了高效稳定的XPW输出,为后续的放大应用提供了高对比度、宽光谱的高质量种子源. 相似文献
14.
15.
Liu D. -F. Zhu X. -J. Wang C. -H. Yu J. -J. Fang E. -X. Wang J. -J. 《Laser Physics》2011,21(2):414-418
We report an all normal dispersion low repetition rate high energy passive mode-locked ytterbium-doped fiber laser with output
pulses duration ranging from nanoseconds to picoseconds. The mode-locking mechanism of the laser is based on nonlinear polarization
evolution and strong pulses shaping with a cascade long-period fiber grating bandpass filtering in highly chirped pulses.
The laser generates highly stable pulses duration from 2.62 ns to 315 ps with a maximum pulse energy of 49.5 nJ and 2.5435
MHz repetition rate. 相似文献
16.
A realistic numerical theory of the temporal and spectral development of picosecond light pulses in a passively mode-locked Nd-glass laser is presented. The effects of the inhomogeneous gain profile of the active medium are considered. The calculations include the pulse development in the prelaser, the linear laser and the mode-locking region. In the mode-locking region twophoton absorption and self-phase modulation in the active medium as well as the bleaching dynamics of the mode-locking dye are included. The influence of self-phase modulation on the temporal pulse shape in active media of finite spectral gain width is analysed. The theoretical results are compared with the experimental findings.This paper is dedicated to Professor W.Kaiser for his 60th birthday. 相似文献
17.
S.R. Chinn 《Optics Communications》1979,31(3):359-362
The effect of etalon frequency selectivity on homogeneously broadened mode-locked laser in the limit of low finisse and narrow free spectral range has been calculated. The etalon does not affect the mode-locked pulse width, but modulates the frequency spectrum and causes small secondary pulses. Significant perturbation occurs when the etalon discrimination is one to two orders of magnitude less than the depth of mode-locking modulation. 相似文献
18.
A Q-switched mode-locking femtosecond all-fiber laser based on a 2 cm long homemade Er3+/Yb3+ codoped phosphate glass fiber has been reported. By using the nonlinear polarization evolution technique, a nearly 100% modulation
depth of mode-locking pulse train is achieved. At a pump power of 410 mW, the energy of each Q-switched envelope, whose width
is about 220 μs, is 10 μJ, while the duration of mode-locking pulse within the Q-switched envelope is 318-fs. 相似文献
19.
利用耦合非线性薛定谔方程(CNLSE)为非线性偏振旋转(NPE)锁模自相似光纤激光器建立了一种新的数值模型.模型中,用CNLSE描述脉冲在单模光纤中的传播,在增益光纤中同时考虑了增益带宽和增益饱和作用,用传输矩阵描述构成NPE锁模的光学元件.优化了腔内净色散和光纤长度等参数,模拟了脉冲在激光腔内的演化特性,得到了典型的自相似脉冲运行区域及特点.在最佳自相似脉冲运行区域内,得到了能量约为7 nJ、脉宽约11 ps、线性啁啾的抛物脉冲.比较了不同腔内净色散条件下输出脉冲的特点,给出了三阶色散对输出脉冲的影响.
关键词:
自相似脉冲
非线性偏振旋转锁模
耦合非线性薛定谔方程
数值模拟 相似文献