Tunable, high-repetition-rate, harmonically mode-locked ytterbium fiber laser

We report a ytterbium fiber laser mode locked at its 281st harmonic, which corresponds to a repetition rate greater than 10 GHz. The laser produces linearly polarized, 2-ps pulses with up to 38-mW of average output power. The mode-locked pulses are tunable over a 58-nm window centered on 1053 nm.     

LD end pumped, actively mode locked and passively Q-switched Nd:YAP laser at 1341 nm

An end pumped Nd:YAP laser at 1341 nm is actively mode locked and passively Q-switched. Pumping was done with a pulsed high power laser diode with maximum power 425 W. V³⁺:YAG with 61% initial transmission served as saturable absorber, and an acousto-optic modulator is used for active mode locking. The output pulse train with 69 ns duration has a total energy of 3.2 mJ with ±4% shot-to-shot fluctuation. The peak output energy of a single mode locked pulse is 0.25 mJ. The pulse duration of a single mode locked pulse is less than 800 ps. The output laser beam is nearly diffraction limited with 1.6 mm diameter, and beam propagation factor M² about 1.3.     

基于KTP键合晶体的Hansch-Couillaud双波长外腔频率锁定机理

基于KTP键合晶体采用Hansch-Couillaud频率锁定技术实现了双波长外腔同时共振,理论和实验上分别研究了基于键合KTP晶体的HC频率锁定方案. 研究表明,与采用单KTP晶体的结果相比,采用键合KTP晶体进行HC锁频时,能将激光频率分别锁定到e₁光或e₂光的共振峰值. 实验中将环形腔腔模频率锁定到938nm激光器的输出频率上,1583nm激光器的输出频率锁定到环形腔腔模频率上,从而实现了三者之间的相位关联锁定. 关键词： 键合KTP晶体 Hansch-Couillaud锁频 双波长外腔共振     

Dual-wavelength passively mode-locked Nd: GdVO4?laser?with?orthogonal polarizations

A passively mode-locked dual-wavelength Nd: GdVO₄ laser with orthogonal polarizations is experimentally demonstrated. By changing the absorbed pump power, the laser can mode lock either at 1063?nm (with ?? polarization) or 1065 nm (with ?? polarization), or simultaneously at both wavelengths with orthogonal polarizations. When mode locked at 1063 nm and 1065?nm, the laser produced pulses of 10?ps and 5.9?ps, respectively, with repetition rates of 143.7?MHz and 143.9?MHz. When simultaneously mode locked at both wavelengths, the pulsewidth was about?7?ps. The laser was demonstrated by exploiting the thermal lens and birefringence of the Nd: GdVO₄ crystal. The laser uses one cavity and does not require the insertion of additional optical components.     

7.13 W全固态1 319 nm宏微脉冲激光器

 研制了一台高效率全固态平均功率7.13 W的1 319 nm宏微脉冲激光器。激光器采用热稳Z形折叠腔,增益模块采用自行研制的准连续15个二极管芯片环形泵浦的Nd:YAG模块,采用主动声光锁模器作为锁模元件,并在腔内插入倍频KTP晶体对激光器的输出尖峰进行抑制。为了获得稳定的锁模状态,对激光器腔长进行了精确设计和调节。当激光器腔长与锁模器驱动频率匹配时,获取了宏脉冲重复频率400 Hz、脉宽约190 μs,微脉冲重复频率95.6 MHz、脉宽小于1.0 ns的1 319 nm激光脉冲。     

超低阈值Q调制，锁模Yb3+光纤环形腔激光器

 在一种掺镱（Yb³⁺）光纤锁模激光器中。谐振腔采用近“8”字形环形结构，并巧妙地引入半导体可饱和吸收镜（SESAM），腔内引入起偏器和偏振控制器，利用非线性偏振旋转的被动锁模机理，结合SESAM慢可饱和吸收体的自启动作用，在极低的泵浦功率下，实现了稳定的调Q脉冲输出和锁模输出。当泵浦功率为18 mW时，调Q脉冲重复频率为16 kHz，脉冲宽度4 μs，光谱宽度为2.34 nm。当泵浦功率为60 mW时，实现了激光器连续锁模，输出功率8 mW，重复频率20 MHz，光谱宽度3.54 nm，脉宽在ps和亚ps量级，而且在调整偏振控制器的角度时，观察到了波长的调谐现象，调谐范围为1 028~1 530 nm。     

激光二极管泵浦的准连续运转飞秒Cr:LiSAF激光器

报道国内第一台用６７０ｎｍ激光二极管泵浦的准连续锁模运转的Ｃｒ：ＬｉＳＡＦ激光器。对于连续运转,泵浦阈值功率２４０ｍＷ,当吸收功率为３６８ｍＷ的输出,输出波长８５０ｎｍ,斜效率为３．５％。在准连续运转（１００ＨＺ,占空比１／５时）,泵清阈值功率４５ｍＷ,斜效率为９．８％,用染料作为锁模妄动介质,实现了准连续锁模运转,光脉冲输出的中心波长为８５０ｎｍ。     

Femtosecond pulse generation with a diode-pumped Yb3+:YVO4 laser

A diode-pumped Yb:YVO4 laser has been passively mode locked for the first time, to our knowledge. 120 fs pulses with an average output power of 300 mW and a peak power as high as 14.5 kW are obtained by use of a semiconductor saturable-absorber mirror for passive mode locking. The optical spectrum has a 10 nm bandwidth (full width at half-maximum) and is centered at 1021 nm.     

SESAM‐free mode‐locked semiconductor disk laser

Experimental demonstration of semiconductor saturable absorber‐free mode‐locked optically pumped semiconductor disk laser is presented. The origin of pulsed operation is attributed to the intensity dependent Kerr lens effect arising in the semiconductor gain medium. Achieved results represent a novel method to mode‐lock this type of laser opening new application opportunities. The laser worked stably in both hard and soft aperture configurations. No semiconductor saturable absorber was used in the laser cavity and the operation was self‐starting. The laser was mode‐locked at 210 MHz repetition rate with 1.5 W average output power and 930 fs pulse width at 985 nm. A record high 6.8 kW peak power was achieved. Measured data is presented along with a discussion of the Kerr lens effect in the cavity.     

Diode-pumped mode-locked Yb:YCOB laser generating 35 fs pulses

Direct sub-50-fs pulse generation is demonstrated with a mode-locked Yb:YCa4O(BO3)3 laser. With external compression, pulses as short as 35 fs are generated at 1055 nm. The oscillator operating at a repetition rate of 95 MHz is pumped by a two-section distributed Bragg reflector tapered diode laser and mode locked by a semiconductor saturable absorber mirror. The onset of self-Raman-conversion for pulse spectral bandwidths exceeding 40 nm (FWHM) is observed.     

Highly efficient mode-locked Yb:Sc2O3 laser

Passive mode locking of the Yb:Sc2O3 laser is demonstrated. We investigate the laser performance with Ti:sapphire and diode-laser pumping. The laser is mode locked by use of a semiconductor saturable-absorber mirror and emits as much as 0.8 W of power in the picosecond range with a pump efficiency as high as 47%. With dispersion compensation, pulses as short as 230 fs for an average power of 0.54 W are obtained at 1044 nm. This is, to our knowledge, the first femtosecond oscillator based on an Yb-doped sesquioxide crystal.     

滤波对8字腔掺铒光纤激光器锁模运转的影响

构建了基于损耗非对称非线性光学环镜的8字腔掺铒光纤锁模激光器,并讨论了腔内滤波带宽对腔内脉冲演化和激光器输出特性的影响.在非线性光学环镜中引入双向输出耦合器,耦合器和传输光纤位置的不对称产生非互易性,实现锁模运转.利用自制的可调谐滤波器实验研究了滤波带宽对激光器的影响.当滤波带宽为2.1 nm时,腔内脉冲的演化过程受滤波和孤子效应的共同作用,激光器顺时针和逆时针输出脉冲半高全宽分别为583.7fs和2.94 ps.随着滤波带宽增大,滤波的作用逐渐减弱,激光器两路输出脉冲参数逐渐接近,并接近傅里叶变换极限脉冲.当滤波带宽较大时,腔内脉冲的演化过程受增益谱和孤子效应的共同作用,激光器顺时针和逆时针输出脉冲均为变换极限脉冲,半高全宽约为440 fs.通过调节滤波器中心波长实现了对激光器输出脉冲光谱的连续调谐,调节范围大于30 nm.     

自锁模Cr：LiSAF激光器的实验研究

以功率为９００ｍＷ，波长为４８８ｎｍ的单线氩离子激光作为泵浦源，在腔内不加任何主动调制器和可饱和吸收体的情况下实现了Ｃｒ：ＬｉＳＡＦ激光器的飞秒级自锁模运转，得到了脉冲宽度为４０ｆｓ，重复频率为１００ＭＨｚ，平均输出功率为４５ｍＷ的稳定的锁模脉冲序列。     

Diode-pumped Yb:Sr(3)Y(BO(3))(3) femtosecond laser

We have developed a diode-pumped Yb(3+)Sr(3)Y(BO(3))(3) (Yb:BOYS) laser generating 69-fs pulses, at a central wavelength of 1062 nm. This laser is mode locked by use of a semiconductor saturable-absorber mirror and emits 80 mW of average power at 113 MHz. This is, to our knowledge, the first mode-locked Yb:BOYS laser and the shortest duration obtained from an ytterbium laser with a crystalline host. The central wavelength can be tuned from 1051 to 1070 nm, for sub-100-fs pulses. We have also achieved an average power as high as 300 mW with pulse duration of 86 fs at 1068 nm.     

Nd,Cr:YAG自调Q自锁模激光器的研究

实验采用光纤耦合激光二极管泵浦,得到了二极管泵浦Nd,CrYAG自调Q自锁模1.064 μm激光输出,其锁模调制深度达到了近100%,其输出功率最高可达1.9 W,平均输出功率稳定性优于1%.实验表明平均输出功率、重复频率和脉冲宽度随泵浦功率增加而上升.     

Diode-end-pumped Nd:CaYAlO4 mode locked laser

A diode pumped passively mode locked Nd:CaYAlO₄ (Nd:CYA) laser is demonstrated for the first time to the authors' knowledge. Using a V-shaped cavity and a semiconductor saturable absorbing mirror (SESAM), self-started mode locking of the laser is experimentally achieved. The mode-locked pulses are as short as 3.9 ps at a central wavelength of 1080.2 nm. The mode-locked laser produced a maximum average output power of 2.25 W with a slope efficiency of 23.2%.     

全光纤多种子激光脉冲产生系统

报道一种可精确同步输出宽带啁啾脉冲、纳秒级整形脉冲以及窄带光参量啁啾放大抽运脉冲的全光纤多种子激光脉冲产生系统.采用掺镱光纤锁模激光器和掺镱单纵模光纤振荡器作为系统的光源,将掺镱光纤锁模激光器输出的超短脉冲分束啁啾展宽至0.9ns后,一路进行放大产生10μJ量级的宽带啁啾脉冲为高能拍瓦激光器系统提供种子光脉冲,另一路通过1.2nm滤波产生140ps的基元脉冲,通过光纤堆积器产生可编程整形的2.3ns脉冲,再经过放大达到10μJ量级,提供任意整形的压缩脉冲.同时,将部分掺镱光纤锁模激光器输出的超短脉冲进行光电转换并锁相后,产生与锁模超短脉冲高精度同步的电脉冲用于触发幅度调制器,将掺镱单纵模光纤振荡器输出的连续光削波放大,产生光参量啁啾放大抽运脉冲.该系统能够根据物理实验的需要,非常灵活地在输出各种脉冲之间做出选择.     

基于Fabry-Perot半导体激光器实现全光波长转换及其最优纵模选择

采用Fabry-Perot半导体激光器作为波长转换器件,利用半导体激光器内部的交叉增益调制效应,通过同时将脉冲信号光与连续探测光耦合到半导体激光器,实现了对波长为1552.62nm、重复速率为2.7GHz的光脉冲信号转换到波长为1548.23nm的连续激光,同时实现了脉冲时间抖动的抑制.实验发现,对于确定的半导体激光器及其工作参数,总存在一个固定的纵模,当探测光的波长与该纵模波长一致时可获得最高的波长转换效率和最大的消光比.理论分析了探测光与Fabry-Perot半导体激光器多纵模间的模式选择对波长转换效 关键词： 纵模选择 波长转换 注入锁定 交叉增益调制     

普通单模石英光纤中频率上转换过程的研究

介绍了在普通通讯用单模ＧｅＯ２／ＳｉＯ２石英光纤中从近红外到可见光的频率上转换过程。利用１．３１３μｍ的调Ｑ锁模Ｎｄ：ＹＬＦ激光脉冲泵浦单模石英光纤，产生了５８８ｎｍ的黄光，峰值功率达２０Ｗ，对应０．０９％的转换效率。     

Room temperature,multi-wavelength operation in Er:YAG

Room temperature, multi-wavelength operation in 0.3% doped Er:YAG laser with double etalons pumped by a MgO:PPLN laser locked at 1532 nm was reported. Lasing occurred predominantly at 1645.1 nm and 1617.2 nm. 350 mW of 1645.1 nm, 160 mW of 1617.2 nm output were achieved under total incident pump power of 7 W.