基于载波相移系统的二倍频光电振荡器

为了扩展光电振荡器(OEO)的频率范围,设计了 一种基于载波相移系统的二倍频OEO(FD-OEO)。 系统采用相位调制器(PM)和Mach-Zehnder调制器(MZM)并联,构成载波相移系统,利用载 波相移双边带(CPS-DSB) 调制的方法产生二次谐波分量;同时利用啁啾光纤布拉格光栅(CFBG)色散特性实现边带分 量与CPS补偿,维持 OEO环路中基频信号的振荡。实验结果显示,在OEO环路系统基频信号为2.23GHz情况下,产生了4.30 GHz的FD信号,且通过边模抑制性能、稳定性及相位噪声对系统性能进行了验证。     

高功率全固态绿光激光技术研究进展

 报道了高功率全固态腔内和腔外倍频两种绿光激光器研究进展。腔内倍频绿光激光器采用L型腔双棒串接结构,在重复频率10 kHz时,用三硼酸锂晶体倍频获得绿光功率186 W,光-光效率达15.8%。腔外倍频绿光激光器采用主振荡和功率放大器,在重复频率400 Hz时,获得基频激光单脉冲能量1.2 J,采用Ⅱ类相位匹配KTP晶体腔外倍频,获得525 mJ的绿光输出,倍频效率为43.7%。采用偏振合成技术获得了单脉冲能量大于1 J的绿光输出。在该激光放大器实验装置上,进行了双模块热效应补偿技术和受激布里渊散射相位共轭技术实验研究,改善了激光光束质量。     

基于单环光电振荡的宽带二倍频信号产生方法

提出了一种基于单环光电振荡器(OEO)的宽带二倍 频信号产生方法。将射频(RF)信号经过第1级马赫-增德尔调制器(MZM)调 制到光信号上,通过控制第1级MZM的偏置电压,使得其工作在最小传输点(MITP)上,产生的 －1阶和+1阶边 带信号通过第2级MZM注入到由单膜光纤(SMF)、光电检测器(PD)和电放大器(amplifier)组成 的光电振荡环腔中,光电检测后产 生二倍频信号,信号的频率稳定度由信号源的稳定度决定,信号的相位噪声由光电振荡环腔 决定。在实验结构简单 的条件下,有效实现了宽带二倍频信号产生。实验结果表明,当本文系统可以实现对C波段 和X波段信号二倍频,输出信号的相位噪声在10kHz偏移处均低于－102dBc/Hz。     

LD泵浦准连续Nd:YAG/KTP 12 W红光激光器

报道了使用国产大功率全固态NdYAG泵浦组件产生1.3 μm附近波长的激光振荡,利用Ⅱ类临界相位匹配的KTP晶体腔内倍频产生高功率的红光激光输出.泵浦组件内包含30个20 W的808 nm二极管阵列,呈三角型阵列分布连续抽运5 mm×125 mm的NdYAG圆棒.为产生高功率的倍频输出,激光器采用V型折叠腔结构,并使用1个声光Q开关.在泵浦功率大约470 W时,产生了12 W的准连续高功率红光激光.     

678 nm RTP electro-optical Q-switched ceramic laser

The RTP electro-optical Q-switched ceramic laser at the wavelength of 678 nm with narrow pulse width is studied. We used the laser diode arrays side-pumped Nd:YAG ceramic crystal with 1.1 at% Nd doping and dimensions of Φ3 mm × 50 mm, designed folding cavity parameters, and discussed the variation of the beam radius in the ceramic crystal and frequency doubling crystal with the thermal focal length of ceramic crystal or KTP crystal. By using double RTP crystals as electro-optic Q-switch and KTP crystal type II phase matching for intracavity frequency-doubling, a narrow pulse width electro-optical Q-switched Nd:YAG ceramic laser was obtained. The output energy of 0.9 mJ and the pulse width of 41.6 ns at 678 nm are obtained at the repetition rate of 1000 Hz and pumped power of 144 W. The results formed the basis for the further development of the high power and high efficiency ceramic red laser.     

Single-Frequency Laser Using a 100-μm Thick Nd:YVO4 Crystal in a 50-mm Long Cavity

A new type of single-frequency solid state laser for achieving a highly stable second-harmonic generation in a simple configuration was developed using a quite thin laser medium. A 100-μm thick Nd:YVO4 crystal with one side coated for high reflection in a 50-mm long cavity which serves as automatic gain discriminator was end-pumped by a laser diode. Single-frequency output powers of 100 mW and 17 mW were obtained for fundamental and second-harmonic waves respectively by 1-W excitation. No chaotic fluctuation was observed with the frequency-doubled output.     

并行PM生成的12倍频毫米波RoF系统研究

提出了一种利用4并行相位调制器(PM)结构调制生成12倍频毫米波的方法,详细介绍了该方法的原理,并通过公式推导证明了其可行性.采用软件搭建了相应的RoF仿真系统,检测到12倍频后毫米波的频谱图和通过系统传输后的眼图.理论分析和仿真结果表明,10GHz的射频信号可产生120GHz的毫米波,5Gb/s的数据可在光纤中传输30km以上,功率代价小于0.9dB.     

KTP倍频器件温度适应性扩展研究

针对目前最常用的KTP倍频晶体, 综合考虑其有效非线性系数和温度半宽度, 采用折中设计有效扩展KTP倍频器件适用温度范围. 对大适用温度范围的KTP倍频器件的设计方法进行了详细的理论分析, 并设计了一种温度半宽度为-20 ℃到50 ℃的KTP倍频器件. 实验结果表明该器件在15 ℃时达到峰值转换效率22.7%, 温度半宽度为70 ℃. 和通常情况下设计的KTP倍频器件相比, 尽管倍频转换效率有所下降, 但显著提高了适用温度范围. 且在温度半宽度高达70 ℃情况下, 其有效非线性系数仍大于LBO, BBO等倍频器件. 该方法对于扩展倍频器件的温度适应性具有普适性.     

LD侧泵全固态Nd∶YAG/KTP高功率连续绿光激光器

报道了LD侧泵全固态Nd∶ YAG/KTP高功率连续绿光激光器.泵浦组件为中科院半导体所生产的808 nm半导体激光器(LD)组件,由9个20 W的激光二极管组成(呈三角形等间距分布),最大泵浦功率为180 W.在平凹直腔的腔型结构下,当LD连续抽运3 mm×65 mm Nd∶ YAG激光棒时,分别选用不同长度的KTP倍频晶体,实现了II类临界相位匹配腔内倍频,最终在泵浦电流22.5 A时,获得了最大功率为21.3 W的连续、稳定532 nm激光输出,输出不稳定度优于2%,光-光(1064～532 nm)转换效率为42.6%.     

Simultaneous Q-switching and Frequency-doubling by a Single KTP Crystal in a Diode-pumped Nd: YVO4 Laser

The interrelation between the phase matching condition for second harmonic generation (SHG) and the electro-optic Q-switching in KTP was numerically analyzed. A diode-pumped Q-switched Nd: YVO4/KTP green laser was reported, where the KTP crystal was simultaneously used as both an electrooptic Q-switcher and a frequency-doubling crystal in type Ⅱ phase matching.Compared with the conventional frequency-doubling and Q-switching configuration, low loss and high efficiency characteristics were realized by using a single KTP crystal. The Q-switched green laser pulse with a peak power of 762 W and a pulse width of 12 ns was obtained with 1 W pump power.