内源形似非稳腔

在高功率固体激光器件中,我们可以用腔损耗较大的非稳腔来获得高光束质量的大模体积的TEM_(00)模输出,但在中小功率的器件中,增益与损耗的矛盾突出。本文从理论与实验出发分析了用内源形似非稳腔可以解决这个矛盾,获得大模体积的TEM_(00)模输出。 所谓内源形似非稳腔,是一种随工作物质热效     

模竞争和交叉弛豫对双频激光器输出特性的影响

双频激光器的稳频特性与其功率调谐曲线的形状有关。本文在理论和实验上研究了模竞争和交叉弛豫对功率调谐曲线的影响,并给出如何选择最佳的磁场和气压,以便获得最好的稳频特性。     

千瓦级CO激光器分子振动态布局分布及输出特性的计算

用一维动力学模型对千瓦级模流自持放电ＣＯ激光器工作特性进行了计算，得到了Ｃ烽Ｎ２分子的振动态布居，利用常数增益光强平均法计算了三程Ｎ形折叠腔的输出功率的温度特性及谱线分布情况，得到了振转过激光输出的振动带及转动支线的详细情况，理论计算与实验结果基本一致。     

环状耦合输出的90°束转非稳腔的模场计算

利用FFT方法对环状耦合输出的90°束转非稳腔在小放大倍率(M=1.2)情况下的模场畸变进行了数值模拟,分析了镜面倾斜和像散对输出光束质量的影响程度,并与常规环形非稳腔进行了比较,结果表明,环状输出90°束转非稳腔比常规环形非稳腔具有更优良的特性.     

环状耦会输出的90°束转非稳腔的模场计算

利用FFT方法对环状耦合输出的90°束转非稳胜在小放大悟率（M=1．2）情况下的模场畸变进行了数值模拟,分析了镜面倾斜和像散对输出光束质量的影响程度,并与常规环形非稳腔进行了比较,结果表明,环状输出90°束转非稳腔比常规环形非稳腔具有更优良的特性。     

全固态激光器的数字式光反馈控制驱动电源

介绍一种采用单片机控制的连续运转无制冷、数字式光反馈稳功率全固态激光器驱动电源,其输出光功率在10mW左右,系统包括恒流源、保护电路、脉宽调制、光电池检测放大电路和高速单片机控制系统等部分,基于光电池检测LD光功率输出的非线性控制曲线产生的误差变化,将特性曲线利用软件的窗口控制算法实现区域控制,进而有效地对LD工作电流进行PID稳态控制和光功率参数显示,结合硬件及软件,实现了激光二极管的可靠保护以及光功率稳定、准确输出及在稳光输出情况下,实现激光器的内外调制输出。     

高单脉冲能量被动调Q锁模Tm,Ho: LLF激光器

报道了一种采用氧化石墨烯作为可饱和吸收体的二极管泵浦的被动调Q和调Q锁模运转的Tm, Ho: LLF激光器。采用透过率分别为3%、5%和9%的输出镜,首先研究了Tm, Ho: LLF激光器的连续运转特性。实验和模拟结果均表明采用透过率为9%的输出镜输出特性最好,当最大泵浦功率为20 W时,连续光输出功率高至1793 mW。接着以氧化石墨烯为饱和吸收体,采用透过率为9%的输出镜研究了Tm, Ho: LLF激光器的调Q和调Q锁模特性。实验表明:当790 nm LD泵浦功率小于7.26 W时,激光处于单纯调Q运转状态;当大于7.26 W时,激光器进入稳定的调Q锁模状态,当最大泵浦功率为20 W时,最大输出功率为1052 mW,锁模重复频率为53.19 MHz,对应的平均单脉冲能量为19.77 nJ,该单脉冲能量是目前2 μm锁模激光器的最高指标,同时证实了氧化石墨烯材料在大能量高功率激光锁模中是发展潜力优良的二维锁模材料。     

全反射棱镜式激光陀螺双纵模稳频技术

针对全反射棱镜式激光陀螺在单纵模稳频条件下纵模调制信号存在盲区的现象,研究了全反射棱镜式激光陀螺双纵模稳频技术。理论分析了功率调谐曲线的特征,获得了双纵模条件下小抖动调制信号的幅度及相位特性,提出了双纵模稳频控制方案,通过软硬件电路设计,搭建了全反射棱镜式激光陀螺双纵模稳频控制系统。在定温和变温环境下,分别对单纵模稳频与双纵模稳频进行了实验测试。实验结果表明,与单纵模稳频控制方法相比,双纵模稳频技术在稳频精度上提高了60%,陀螺精度也得到了相应的提高。     

高稳定度窄线宽激光器的研究

介绍了3种不同类型的高稳定度窄线宽激光器的研究进展.基于Littman结构和饱和吸收光谱稳频技术,研制了稳频外腔半导体激光器系统,输出波长为780.2 nm,频率稳定度1 MHz,不失锁时间大于12 h.利用边带稳频技术将分布反馈(DFB)激光器的输出波长稳定在Cs原子的吸收谱线的边带处,引入数字信号处理器(DSP)全数字稳频控制技术,实现了自动找频和稳频,获得波长为852.3 nm的稳频激光输出,24 h内频率漂移为±2 MHz.利用国产磷酸盐玻璃光纤作为增益介质,实现了一台高功率单纵模光纤激光器,制作的厘米级激光器实现了最大输出功率100 mW,利用外部光反馈实现单偏振运转,测得输出线宽为2 kHz,偏振消光比优于35 dB.     

45°功率分割正交模变换器的分析

由于45°功率分割正交模变换器结构的对称性,输出端正交的TE10和TE01模功率分配理论上是等分的。但在HFSS仿真计算时,由于输出端方口径波导简并模的影响,得到的两正交模功率分配却不相等。为了解决仿真中的功率不等分问题,我们提出对输出端方口径进行微扰的方法,并对微扰孔的位置进行了探讨;分析了加工误差对功率等分性能的影响。     

交错式单管正激变换的半导体激光器电源研究

为了简化半导体激光器电源的电路结构、提升其电能转换效率、实现输出电流的快速动态响应,采用单管正激变换的并联交错技术,设计出一种2kW单级变换的开关型直流驱动电源。测试并分析了电源的静态特性、动态特性及电能转换效率。结果表明,电源的效率高达85%;输出电流0A～100A的上升、下降时间仅为1ms;满载100A工作时,输出电流的纹波系数仅为0.04%。与两级串联结构的半导体激光器电源相比,电源的效率得以提升,输出电流的动态响应速度迅速,满足激光加工的要求。     

热焦距的动态测量

本文对连续（ＣＷ）Ｎｄ＾３＋：ＹＡＧ激光器的热焦距分别进行了静态和动态下的测量。结果表明在同样泵浦功率下,Ｎｄ：ＹＡＧ棒动态下的热焦距比静态下的热焦距要大。从而为精度要求比较高的谐振腔设计提供了更为精确的数据。     

两相两重斩波变换的半导体激光器电源研究

为了提高传统线性半导体激光器电源的电能转换效率、输出电流的动态响应以及对负载电压的自适应能力,采用两相两重斩波变换技术,设计了一种半导体激光器用2kW直流驱动电源。测试并分析了该电源在激光系统中的静态特性、动态特性以及两相两重斩波变换电流源的效率。结果表明,电源对负载电压自适应能力强,具有较好的矩形输出特性;直接驱动激光二极管模块时,该电流源的电能转换效率高达93%,输出电流0A~100A的上升、下降时间仅为0.5ms,电流纹波系数小于0.03%。     

LD泵浦的声光调Q 1.34 μm Nd:GdVO4激光器

对于连续泵浦的内腔式倍频、参量振荡等非线性激光器件,常需要准连续运转来提高腔内的峰值功率,声光调Q是目前获得准连续运转激光器的重要途径。在LD端泵a向生长Nd:GdVO4晶体1.34 μm静态激光的基础上,利用声光调Q对1.34 μm的动态激光进行了实验研究。当声光调Q器件重复率为5 kHz时,获得的最短脉宽为170 ns,此时的单脉冲能量为44.8 μJ,峰值功率为256 W。实验表明,1.34 μm平均功率随声光调Q的重复率增加而增大,脉冲宽度随重复率的减小而变短,因而低重复率下可得到更高的峰值输出功率。     

Transient dynamics of CW intracavity singly resonant opticalparametric oscillators

We study the transient dynamics of CW intracavity, singly-resonant optical parametric oscillators (ICSROs). Relaxation oscillations of the 1064-nm pump light are measured, in both the presence and absence of parametric conversion, in a periodically poled LiNbO₃ (PPLN) CW ICSRO pumped intracavity to a Nd:YVO₄ laser. The presence of parametric conversion is shown to significantly increase both the damping times and oscillation frequencies of the dynamics; at three times the parametric oscillator threshold, these take values of 200 μs and 2 MHz, respectively. Oscillation frequencies are shown to be in good agreement with theoretical values. The influence of energy diffusion and thermal lensing are analyzed to account for discrepences between measured and theoretical damping times. We discuss the implications of the dynamic behavior to the stable-power operation of CW ICSROs     

Dynamics in a compound cavity semiconductor laser induced by smallexternal-cavity-length change

For the short-range variations of the external cavity length, the dynamic behaviors of a semiconductor laser with optical feedback are investigated by the numerical simulations and experiments. Under the condition of a single-mode oscillation, the laser output power shows periodic undulation along the external cavity length whose period is equal to half of the optical wavelength. At weak to moderate external optical feedback, stable, periodic, quasi-periodic, and chaotic oscillations of the laser output power are observed within the periodic undulation. Experimental results of periodic and quasi-periodic oscillations obtained by the laser output power and the optical spectrum support the predictions from the numerical analysis based on the rate equations     

Dynamic single-mode semiconductor lasers with a distributed reflector

Recent progress in the dynamic single-mode (DSM) semiconductor lasers in the wavelength of1.5-1.6mum are reviewed and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to the wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 μm. A DSM laser consists of a mode-selective resonator and a transverse-mode-controlled waveguide, such as the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under the rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some of DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of the art DSM lasers are reviewed. The dynamic Spectral width of 0.3 nm, the output power of a few milliwatts, and the reliability over a few thousand hours are reported for experimental DSM lasers.     

1064nm可编程半导体激光脉冲种子源的研究

为了运用主振功率放大技术获得纳秒量级的高功率密度激光脉冲,设计了一种运用于主振功率放大的半导体激光种子源,通过编程可输出多种形状光脉冲,并采用主动脉冲外形控制技术提高了输出光脉冲的波形质量。实验中研制了高速大电流驱动模块和可编程多种调制波形发生器,并采用了1064nm量子阱分布反馈的大功率半导体激光器。结果表明,该种子源脉冲光功率优于200mW、动态范围优于20dB、脉冲宽度40ns~1μs和重复频率0MHz~5MHz可调,可编程控制输出多种波形。     

Nonlinear dynamics of a laser diode with optical feedback systemssubject to modulation

The nonlinear dynamic behavior of a direct frequency-modulated diode laser with strong optical feedback is examined and compared to a laser diode subject to electro-optically modulated, strong optical feedback. Direct modulation is achieved by sinusoidal modulation of the diode laser injection current. Electro-optic modulation is achieved by applying a sinusoidal voltage to an intracavity phase modulating element. The output state (characterized by the output power versus time, the intensity noise spectrum and the optical frequency spectrum) for both types of modulation is dependent on the ratio of the modulation frequency to the external cavity resonant frequency, and the modulation power. A number of distinct states are observed: conventional amplitude modulation (with FM spectra); multimode, low-noise amplitude modulation; multimode, high-noise amplitude modulation; periodic limit-cycle operation; quasi-periodicity; chaos; low-frequency fluctuations; and mode-locking. There are significant differences between the direct and electro-optic frequency-modulation cases. The onset of the dynamic instability is characterized as a noisy period-one oscillation for direct modulation and a low-frequency fluctuation for intracavity electro-optic modulation. Phase portraits produced experimentally with the use of a digital phosphor oscilloscope are shown to agree well with those constructed from output power versus time data. This represents an experimental method for examining the dynamics phase portraits in real-time