论述一种新的激光脉冲整形方法-利用任意形状的整形电脉冲直接驱动半导体激光器,产生与电脉冲形状一致的激光脉冲,作为高功率激光装置的种子光源。使用GaAs场效应管作为开关器件,使用超宽带脉冲触发场效应管产生整形电脉冲,引入阻抗渐变微带技术克服了触发脉冲损耗对级联场效应管数量限制,将整形电脉冲脉冲宽度扩展到10 ns。以整形电脉冲直接驱动半导体激光器,可产生脉宽为10 ns,时域调节精度为330 ps的任意整形激光脉冲。

Pulse shaping techniq ue is of great significance for high power laser facility. In this paper, a new method used in laser pulse shaping system was proposed. An arbitrary waveform generator was fabricated to generate shaping electrical pulse. GaAs Field Effect Transistor (FET) has good ability of generating voltage-controlled current and on-off characteristic, while the semiconductor laser contains direct modulate characteristic. The unit-pulse was generated based on the on-off characteristic of GaAs FET, and then the arbitrary waveform electrical pulse was generated by stacking a set of unit-pulses. Impedance tapered micro-strip line was designed to maintain the consistency of each unit-pulse. The arbitrary waveform electrical pulse was used as shaping electrical pulse to modulate the semiconductor laser directly to realize the laser pulse shaping . With this method , a laser pulse waveform was generated with duration less than 10 ns, 330 ps time-domain adjustment. The experiment resu

利用主振荡功率放大(MOPA)结构高功率皮秒脉冲全光纤激光器,对高功率皮秒脉冲放大器中自相位调制(SPM)效应进行了实验研究。激光器种子源是自行搭建的半导体可饱和吸收镜(SESAM)被动锁模光纤激光器。为了抑制非线性效应,使用一个自制重频倍增器把种子脉冲的重频增加到328 MHz后再放大。放大器部分采用三级放大结构,最终获得了中心波长为1 066.5 nm,3 dB光谱线宽约为2.5nm,平均功率为91W的稳定皮秒脉冲激光输出。实验对光脉冲在放大的过程中自相位调制引起的光谱变化进行了研究。对激光器输出光谱的分析表明,随着功率的增大,高功率光纤激光器中自相位调制效应受到入射脉冲的初始啁啾和脉冲形状的影响程度也随着变大,与此同时还受到自陡峭效应的影响。

An experimental research on self-phase modulation (SPM) of high power picosecond pulse amplifier was conducted by high-power all-fiber picosecond pulse fiber laser with an MOPA configuration. The seed source is a self-built fiber laser passively mode-locked by semiconductor saturable absorber mirror (SESAM). To avoid nonlinear effect, the repetition rate of the seed pulse should be increased to 328 MHz through a self-made repetition multiplier before amplification. The amplifier employed a three-level amplifying structure and finally received a stable picosecond pulse laser output with a center wavelength of 1 066.5 nm, a 3 dB spectrum width of 2.5 nm, and an average power of 91 W. In the experiment, there was research on change of spectrum caused by SPM in the process of amplification. An analysis of the output spectrum of the laser demonstrates that with the increase of power, the influence of the initial chirp and the shape of the pulse on the SPM effect of high power fibe

为获得脉冲宽度窄、前沿上升速度快的大功率激光输出，以提高激光引信等武器装备抗干扰的性能，设计出了一种由高压电源、驱动电路及多管芯激光器组成的高功率窄脉冲半导体激光器模块。激光器采用多管芯串并联组合发光的方式，驱动电路部分实现高压储能放电，使用了高速开关断器件MOSFET作为LD放电回路的开关，应用板载技术进行封装。在较大光功率输出的同时，脉冲波形宽度更窄、前沿上升速度更快。最后经OrCAD/Pspice软件进行仿真分析。实验结果表明，模块实现了高功率窄脉冲的激光输出，得到脉冲宽度为8ns、上升时间为2ns的窄脉冲，最大输出功率可达200W。

In order to get a short rise time and narrow-pulse width with high-power output light to improve the ability of resistance to environmental interference in many military areas like laser fuze area, the narrow-pulse semiconductor laser module was designed,which was consists of high-voltage power,drive circuit and multi-die laser. A combination of the laser multi-chip array structure emitting way was used in the semiconductor laser. A high voltage storage was used in the driving circuit and the high speed switching component MOSFET as the switch of the LD discharge circuit and packaged with on-board technology. In contrast,a larger optical power output with a narrower pulse waveform and a faster front rising were got, the rise time of the pulse leading edge was effectively shortened and a more narrow pulse waveform was exported. Finally, the LD discharge circuit was simulated and a pulse width of 8ns and narrow pulse rise time less than 2ns by OrCAD / Pspice were got. The maxim

为了减小长腔长高功率单管半导体激光器在封装过程中引入的热应力,根据应力改变禁带宽度的原理,理论上推导了应力与波长漂移的关系,提出了一种通过测量激光器脉冲条件下的光谱来定量计算激光器应力的方法。利用这种方法得到的研究结果表明,焊接质量直接决定着应力的大小,由焊接质量的不同引起的应力差值超过了300MPa,提出了优化焊接回流曲线的方法,使激光器的应力由原来129.7 MPa降低到53.4MPa,该方法还有效的解决了封装应力随储存时间变化的问题。实验表明,激光器光谱图的测量分析是研究高功率单管半导体激光器封装应力的有效方法,也是检测分析烧结工艺的有效手段。

To reduce packaging-induced stress of long cavity length high-power single emitter semiconductor laser,the relation-ship between the stress and the wavelength shift was deduced on the basis of the theory that the stress can change the band gap. A method was developed for quantitatively calculating the stress by measuring the emission spectrum of the laser under pulse conditions.The results show that the soldering quality is a critical factor affecting thermal stress.The difference in stress can exceed 300 MPa due to the difference in soldering quality.By optimizing the reflowing soldering curve of the laser,the stress of the laser drops from 129. 7 to 53. 4 MPa.This method can also effectively solve the problem that the stress varies with storage time.This work demonstrates that the measurement and analysis of the emission spectrum of the laser can provide a useful meth-od to study packaging stress of the high-power single emitter semiconductor laser.It is also an available means to ev

使用连续式输出的砷化镓半导体激光器泵浦的掺钕钒酸钇激光器作为光源，被动式通过轴棱锥产生Bessel光束。在激光谐振腔内加入Cr4＋：YAG晶体调Q产生脉冲Bessel光束。理论模拟了1064 nm波长光束经过轴棱锥之后的三维传播图和截面光强分布。通过实验得到了1064 nm波长脉冲Bessel光束的脉冲宽度和脉冲重复率，并计算得到了单脉冲Bessel光束的能量和峰值功率。利用光束分析仪记录了1064 nm波长Bessel光束的截面光强分布，并测量了中心光斑的直径，得到的数据与理论计算基本吻合。

The laser diode pumped Nd:YVO4 laser was used as light source, Bessel beam was generated by passively passing through axicon. The pulsed Bessel beam was generated by putting the Cr4+:YAG in the laser resonator. The propagation and cross- section distribution of 1 064 nm Bessel beam were simulated. In experiment, the pulse width and pulse repetition rate of 1 064 nm pulse Bessel beam were obtained, the energy and the peak power of pulsed Bessel beam were calculated. The cross- section intensity distribution of Bessel beam was recorded by the laser beam analysis and the diameter of centre spot was measured. The experimental results agrees well with the simulation.