8字形主被动锁模掺Er3+光纤激光器

在理论上分析了利用非线性光学环形镜作为等效可饱和吸收体压缩脉冲进行锁模的物理机制。利用8字形主被动混合锁模的结构在调制频率2．498749GHz下，在1．543μm处获得了12ps的锁模脉冲输出，对应谱宽0．22nm，时间脉宽积0．33。在抽运功率50mW情况下，输出脉冲平均功率3．715mW。在调制频率2．499344GHz、2．499114GHz和2．498999GHz时分别并获得了2～4阶幅度较为均衡的有理数谐波锁模脉冲序列。     

Colliding pulse mode-locked Nd: YLF laser with negative feedback control by GaAs Photoconductive switch

A picosecond colliding pulse mode-locked Nd: YLF laser with negative feedback provided by GaAs photoconductive switch was described. Optical pulse with～4ps duration, 10μJ energy and about 7μs long pulse train were generated.     

Simple picosecond dye laser system pumped by a frequency doubled,optically compressed Q-switched mode-locked Nd:YAG laser

Using the frequency doubled output of the 3 ps pulses from a temporally compressed cw Q-switched and mode-locked Nd:YAG laser, a simple synchronously pumped dye laser was constructed to give frequency tunable operation with short pulses in the 5–10 ps range and peak powers of ～ 15 kW. A circularly scanning streak camera operating in stroboscopic mode was also used to examine pulse formation in the dye laser.     

808nm波长光纤耦合高功率半导体激光器

In this paper, we report the stabilized 10-GHz actively mode-locked fiber ring laser constructed with non-polarization-maintained fiber. Long term stabilization was achieved by synchronous modulation technology, based on an error signal extraction and procession circuit. The output pulses maintained very well over 8 hours with the pulse width of ～11 ps and the spectrum width of ～0.37 nm. Meanwhile the output power and the center wavelength of the output pulse also kept stable at 1.6 mW and 1550.3 nm respectively. The output pulses were additionally compressed to 2 ps by high order soliton effect.     

基于色散不对称光纤环形镜的锁模光纤激光器

在理论上数值计算了各种常量对色散不对称非线性光纤环形镜透射特性的影响。并分析了它作为被动锁模器件用于光纤激光器压窄脉冲的物理机制。利用8字形主被动混合锁模的结构在调制频率为9．998748700 GHz，波长为1566．65nm处获得了11ps的稳定锁模脉冲输出．对应谱宽0．297nm．同时在重复频率为9．995792825 GHz和9．996778256 GHz时分别得到了振幅均匀的二阶和三阶谐波锁模输出。证明色散不对称非线性光纤环形镜可以有效消减脉冲的尾翼和噪声．得到脉幅稳定的脉冲序列。     

Robust diode-end-pumped Nd:GdVO4 laser passively mode-locked with saturable output coupler

Passively mode-locked diode-pumped solid-state (DPSS) Nd:GdVO₄ laser by using a saturable output coupler (SOC) in stable two-mirror linear cavity design is demonstrated. The laser was pumped by low-power single laser diode without any active cooling and external optics. Robust CW mode-locked operation was obtained with a repetition of 150–250 MHz, the pulsewidth was 12 ps, the lowest threshold for CW mode-locked was 185 mW. The optimal condition is found when the laser provides the set of characteristics: low CW mode-locking threshold (～260 mW), compact size (total cavity length 60 cm), good efficiency (～20%), and very stable output. At the output power of 270 mW an average power fluctuations within ±2% for long-term operation was obtained.     

All-fiber passive mode-locked laser to generate ps pulses based in a symmetrical NOLM

We experimentally investigate an all-fiber passively mode-locked laser generating ps pulses. The experimental setup is a figure eight fiber laser configuration, including a power-symmetric Nonlinear Optical Loop Mirror (NOLM) with highly twisted low-birefringence fiber in the loop. NOLM switching is achieved by polarization asymmetry between the counter-propagating beams in the loop. We used a Quarter-Wave Retarder in the loop to break the polarization symmetry. Using a polarizer beam-splitter cube as the NOLM output we got the best quality output pulses from the laser. At this output, we are monitoring the output pulse polarization component which is parallel to the input NOLM component. We achieved stable generation of ～25 ps pulses at the repetition frequency of 0.78 MHz with milliwatts average output power. The mode-locked laser ran in stable operation for hours.     

Diode pumped actively mode-locked Tm:YAlO3 laser

CW acousto-optical mode-locked diode pumped Tm:YAlO₃ laser at 1.936 μm was experimentally studied. Lasing with output power ～100 mW, pulse repetition rate 103.4 MHz and laser pulse durations in the range of 30–200 ps was realized. The problem of laser intensity stabilization is discussed.     

Picosecond laser system with 30-W average power via cavity dumping and amplifying

We present a picosecond laser system with high energy by technologies of cavity dumping and amplifying. Firstly, pulses with 10 ps and ～520 nJ were obtained by cavity-dumped mode-locked laser at 10 kHz repetition rate. Secondly those pulses were seeded into a side-pumped regenerative amplifier (RA). Then pulses output from the regenerative amplifier were amplified by two four-pass post amplifiers. From the laser system pulses with an average power of 30 W corresponding to 3 mJ pulse energy were achieved with the pulse-width of 25.4 ps at repetition rate of 10 kHz.     

10GHz可调谐主动锁模光纤激光器

主动锁模光纤激光器研制的难点在于克服不稳定性,本文提出解决其长期和短期不稳定的方法,分析了它们的工作原理,通过试验证明该两项技术使主动锁模光纤激光器实现了自稳定运转,在全部采用国产非保偏光纤的条件下稳定运行时间超过8h,激光器重复频率为10GHz,脉宽10ps,谱宽为0.317nm,时间带宽积为0.403,调谐范围为39nm。     

超短光脉冲的单延迟三次相关测试

超短光脉冲的对称性可以用单延迟三次相关测试来测定,若再与二次相关测试所得的结果进行比较,可以得到更多的关于脉冲形伏的信息,经测定,Nd:YAG被动锁模激光器的脉冲形状可近似认为高斯-指数形,三次相关函数宽度为22.3ps+15.7ps,对应脉冲宽度为27ps,脉冲的前沿陡于后沿。 关键词：     

Diode-pumped passively mode-locked lasers with high average power

We discuss challenges arising from the quest for high average powers from passively mode-locked diode-pumped lasers. The recently obtained detailed understanding of Q-switching instabilities in passively mode-locked lasers turns out to be a crucial element on the way towards higher powers. We give an overview on results achieved with Nd:YAG (10.7 W, 16 ps and 27 W, 19 ps), Yb:YAG (8.1 W, 2.2 ps and 16 W, 0.7 ps) and Nd:glass (1.4 W, 275 fs).     

汤姆逊硬X射线源中锁模脉冲激光稳频方法

 汤姆逊硬X射线源中,光阴极微波电子枪要求触发激光脉冲与腔中微波场相位的精确时间同步。理论分析了锁模脉冲激光器相位噪声,探讨了对激光脉冲相位探测和控制的方法,并通过实验构建了激光相位抖动测量系统和锁相环稳频回路,用基频鉴相信号驱动压电陶瓷晶体改变谐振腔长,实现了从开环3.42 ps到闭环1.46 ps的均方根相位抖动的测量和控制。     

脉宽易变的高功率Nd:YAG激光器

本文描述一台由两级Nd:YAG激光器组成的紧凑高功率激光系统的结构及其工作性能。激光系统分成三个部分:对撞脉冲式的主-被动锁模振荡器,单脉冲选择器和四程放大器。振荡器输出锁模脉冲列的包络幅度起伏小于±4％,其脉冲宽度可以在宽范围内(20ps～2.5ns)方便地切换。对于单个0.1mJ、200ps的激光脉冲,四程放大器能提供7×10~2的放大倍数。     

Background-free measurement of time behaviour of an individual picosecond laser pulse

A background-free measurement of an individual pulse of a passively mode-locked Nd: glass laser during one laser shot has been performed using a crystal of LiIO₃. The method is based on the non-collinearly generated second harmonic intensity spatial distribution measurement. The time resolution was better than 0.1 ps. The method can be successfully used for picosecond pulse measurement of any laser source over a wide wavelength region.     

All-fiber passively mode-locked laser oscillator at 1.5 microm with watts-level average output power and high repetition rate

We report on a passively mode-locked all-fiber laser oscillator at 1.5 microm based on heavily doped phosphate-glass active fiber. An active fiber only 20 cm long is sufficient to produce as much as 2.4 W of average output power directly from the oscillator. The width of the mode-locked pulses varies from 8 ps at the lowest output power in the mode-locked state to 44 ps at the highest power. Our picosecond laser oscillator features a high repetition rate of 95 MHz and high peak pulse power of approximately 540 W. The oscillator combines the convenience of all-fiber construction with power performance that was previously achievable only with mode-locked bulk-optic laser oscillators or more complex systems involving fiber amplifiers.     

LD Pumped Q-Switching and Self-starting Mode-locked All Fiber Laser

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Diode-pumped passively mode-locked Nd:CTGG disordered crystal laser

A diode-pumped passively mode-locked Nd: CTGG disordered crystal laser has been experimentally demonstrated for the first time to our knowledge. Mode locked with a semiconductor saturable absorber mirror, the laser generated 5.2 ps pulses at a repetition rate of 88 MHz. After intracavity dispersion compensation, the mode-locked pulses were shortened to 4.3 ps. Multiple emission wavelengths of the Nd:CTGG laser could be synchronously mode locked under dispersion compensation.     

Figure-eight actively-passively mode-locked erbium-doped fiber laser

The advantages of using nonlinear optical loop mirror (NOLM) to compress pulse with slight amplitude fluctuation and reflected energy loss are analyzed in theory. Experimentally the NOLM is placed in an actively mode-locked erbium-doped fiber ring laser to form a figure-eight actively and passively mode-locked fiber laser. 12 ps mode-locked pulses centered at 1.543 μm were obtained with the modulation frequency of 2.498748700 GHz. 3.715 mW output power is achieved with 50 mW pump power.     

对采用BBO晶体锁模Nd：YAG激光器的实验研究

报道了在Nd:YAG激光器中使用BBO倍频晶体进行锁模运转的研究结果.获得的二次谐波单脉冲宽度为28ps.锁模序列脉冲能量为lnJ.