宽带波长可调固体染料光放大的实现

对有机染料4－Dieyanomethylene-2-methjyl-6-(p-dimethylaminostyryl)-4H-pyran(DCM)掺杂的PMMA（聚甲基丙烯酸甲酯）以及DCM掺杂的PMMA／凝胶玻璃复合材料平面光波导中的放大自发辐射进行了研究。实验表明,通过合理地控制波导层的折射率及厚度,可以在较宽范围内选择放大自发辐射的波长,从而实现波长调谐,波长调谐范围可达30nm。该方法可应用于固体可调谐激光器及光放大器的宽带调谐。     

环形腔声光可调谐掺铒光纤激光器调谐范围的研究

介绍了一种基于声光可调谐滤波器(AOTF)的可调谐掺铒光纤激光器。从掺铒光纤放大器的速率方程和传输方程出发,推导出声光可调谐掺铒光纤激光器的输出公式,理论上解释了该环形腔声光可调谐掺铒光纤激光器调谐范围仅决定于掺铒光纤的增益带宽;并在实验中测得该激光器调谐范围为1 526.05 nm到1 560.63 nm,这个区间对应着实验所得掺铒光纤自发辐射谱的增益区间,从而验证了理论推导所得结论。     

光纤参量器件研究进展

综述介绍基于光纤四波混频效应的一些参量器件(放大器、频率转换器、相位共轭器等)的物理特性和工作性能;以及基于这些参量器件的新应用,比如可调谐辐射产生、相位敏感放大器、基于频率转换和色散的缓存以及实时采样等;最后就量子信息实验中的光子产生和频率转换等方面进行一些介绍。     

基于约瑟夫森参量放大原理的射频微波相位传感器

近期,利用超导量子干涉器(SQUID)的非线性电感效应,种类多样的参量放大器被广泛研究,证明其对射频微波信号,尤其是信号的相位变化响应灵敏。通过实验研究证明了基于约瑟夫森参量放大器的射频微波相位传感器。实验中采用的约瑟夫森参量放大器由一个嵌入超导共面波导谐振器中的DC SQUID构建而成。由于本次样品中SQUID的临界电流较大,一定程度上限制了参量放大器的非线性与可调谐性,可观测到的相位响应灵敏度为1.2 dB/rad。未来通过合理设计样品,降低临界电流值,必将大幅提高相位传感器的灵敏度。     

新型结构可调谐全光波长转换器的理论与实验研究

可调谐波长转换器是智能化光网络中的关键光电子器件. 提出了一种基于半导体光放大器的环形激光器实现连续可调全光波长转换的方案，建立了该方案的理论模型. 理论计算和实际测定了不同条件下波长转换的输出特性，实验结果与理论计算基本符合. 实验中实现了40nm范围内连续可调、转换速率为2.5Gb/s的交叉增益调制型波长转换. 关键词： 可调谐波长转换 半导体光放大器 环形腔     

基于CIC的数字正交锁相放大器的甲烷检测实验研究

针对甲烷在大气中背景气体成分复杂、检测难度大、稳定性差等问题,本文基于可调谐二极管激光吸收光谱技术和波长调制光谱技术,将积分梳状滤波器与有限脉冲响应滤波器相结合应用于数字正交锁相放大器,开展大气中甲烷气体的痕量检测实验研究.实验表明,与传统的数字正交锁相放大器相比较,改进的数字正交锁相放大器提取的二次谐波信号的信噪比从...     

双光子吸收光谱

本文报道以皮秒脉冲激光抽运的光参量放大器为宽带可调谐激发光源，直接测量非线性光学材料的双光子吸收谱的方法。光参量放大器不但可调谐谱带很宽，而且可用一对尼科尔棱镜很容易地实现全波段功率足够强和相等，使此方法的测量结果准确可靠。用此方法研究了一个新有机化合物的双光子吸收谱。实验结果表明所测的新有机化合物在很宽的波长范围内呈现出很大的双光子吸收截面。     

基于超连续谱的可调谐同步脉冲产生及噪声分析

实验研究了基于超连续谱滤波的可调谐双色同步皮秒脉冲产生技术,将全保偏掺铒锁模光纤激光器输出的脉冲分为两路,其中一路耦合到高非线性光纤,获得了覆盖掺镱光纤发射谱带的超连续谱,通过结合窄带可调谐滤波器和全保偏掺镱放大器,实现了平均功率为70 mW,脉冲宽度为4.0 ps,中心波长为1025～1055 nm的可调谐脉冲。掺铒光纤激光器的另一路输出光经过窄带滤波器和掺铒光纤放大器,实现了中心波长为1580 nm,平均功率为200 mW,脉冲宽度为4.2 ps的激光输出。上述基于超连续谱滤波的可调谐双色皮秒脉冲具有良好的同步特性,可以作为相干反斯托克斯拉曼散射的泵浦光和斯托克斯光。研究发现,选取超连续谱平坦位置的光谱成分作为掺镱放大器的种子光时,脉冲幅值及平均功率抖动更小,相对强度噪声更低。     

基于半导体光放大器的脉宽可调谐暗脉冲激光器

利用半导体光放大器(SOA)实现了一种脉宽可调谐的暗脉冲光纤激光器。将基于SOA的光纤激光器的一部分输出反馈注入SOA,由于SOA的非线性偏振旋转效应,输出脉冲经历不同的偏振演化,从而得到暗脉冲输出。通过改变反馈腔长度可以实现暗脉冲的脉宽调谐。分析了半导体光放大器的非线性偏振效应及暗脉冲的产生机理。并在实验中观察到了脉宽可调谐的暗脉冲输出。通过改变反馈腔长,在重复频率不变(11.31 MHz)的条件下,得到了脉宽为5.91~22.34 ns可调的暗脉冲。     

可调谐半导体环形激光器与FWM全光波长变换实验研究

优化设计半导体光纤环形激光器(SFRL)产生波长连续可调谐窄线宽的激光输出,可调谐范围为40nm,利用半导体光放大器(SOA)的非线性效应四波混频(FWM),实现了码速为2.5Gb/sSDH信号光的波长变换,向上变换7.07nm,向下变换19.49nm.在实验中不需要外加泵浦光源.     

计算机在放大器频率特性研究实验中的应用

本文介绍了用计算机辅助设计的方法研究放大器的频率特性，阐述了将计算机引入物理实验教学的优点和必要性。     

文氏桥振荡器实验中两个现象的分析

对氏桥振荡器实验中两个现象进行了电路分析,给出了振荡频率和幅值条件的修正式,指出电容损耗是引起频率误差的主要原因,同时电容损耗也会影响幅值条件,进而说明实验时应选择优质电容,才能减小频率误差,并使调频不影响输出幅度,从而实现频率与幅度的独立调整。     

Auditory two-tone suppression from a subcritical Hopf cochlea

Cochlear two-tone suppression is the dominant contrast-sharpening phenomenon of hearing and provides a decisive test for the correct implementation of hearing nonlinearities in models of the cochlea. Although critically tuned Hopf amplifiers were shown recently to be fruitful models of intricate phenomena in the physiology of the human ear, we find that only a model based on subcritical Hopf amplifiers is capable of reproducing physiologically measured two-tone suppression data adequately. In addition, we provide a detailed explanation of the two-tone suppression phenomenon, including its quantitative characterization.     

A FULLY ELECTRONICALLY TUNED 283–365 GHz LOCAL OSCILLATOR

A fully electronically tuned 283–365 GHz local oscillator developed for radio astronomical applications is presented. The source is constructed with a 15.7–20.3 GHz YIG oscillator followed by multipliers and amplifiers. It is shown that eliminating spurious harmonic products is essential in achieving low-noise operation of mixers pumped by this LO. This is done with suitable filters, the design of which is described.     

Bandwidth enhancement for parametric amplifiers operated in chirped multi-beam mode

In this paper we discuss the bandwidth enhancement that can be achieved in multi-Joule optical parametric chirped pulse amplification (OPCPA) systems exploiting the tunability of parametric amplification. In particular, we consider a pair of single pass amplifiers based on potassium-dideuterium-phosphate (DKDP), pumped by the second harmonic of Nd:glass and tuned to amplify adjacent regions of the signal spectrum. We demonstrate that a bandwidth enhancement upto 50% is possible in two configurations; in the first case, one of the two amplifiers is operated near its non-collinear broadband limit; to allow for effective recombination and recompression of the outgoing signals this configuration requires filtering and phase manipulation of the spectral tail of the amplified pulses. In the second case, effective recombination can be achieved simply by spectral filtering: in this configuration, the optimization of the parameters of the amplifiers (pulse, crystal orientation, and crystal length) does not follow the recipes of non-collinear OPCPA.     

染料激光放大器最佳增益长度研究

在横向泵浦脉冲染料激光器中,虑及染料激发态在激光波长处的吸收,根据稳态运转转条件,应用极值原理,给出其最佳增益与染料长度的关系式。     

Dual-order Raman fiber laser with suppressed low-frequency pump-to-stokes RIN transfer

By employing an output-power clamping technique, a dual-order Raman fiber laser (RFL) is theoretically presented with suppressed low-frequency relative-intensity-noise (RIN) transfer from pump sources to both first- and second-order Stokes output. Their powers can be easily tuned in a large dynamic range. Furthermore, the second-order output power can be individually controlled, which makes it flexible to adjust the ratio of the first- to second-order output power. In addition, the stabilization of low-power second-order output is also accomplished in the RFL setup. These properties fit the proposed RFL for use as dual-order pump sources in Raman fiber amplifiers.     

染料激光放大器最佳增益长度研究

在横向泵浦脉冲染料激光器中,虑及染料激发态在激光波长处的吸收,根据稳态运转转条件,应用极值原理,给出其最佳增益与染料长度的关系式。     

Coherent Beam Combination of Three Fiber Amplifiers with Multi-dithering Technique

Coherent beam combination of three W-level fiber amplifiers with multi-dithering technique is demonstrated. The multi-dithering technique is used for phase control in two channels. In the experiment, two channels are modulated by sine wave with 70 kHz and 100 kHz respectively, and two regular commercial DSP lock-in amplifiers and an industrial computer are used for electric signal processing in the feedback loop. The fringe contrast is advanced from 12% to 81%, and 78% coherent combination efficiency is obtained when the feedback loop is closed.     

高能量全光纤2 μm掺铥脉冲光纤激光器

基于增益开关技术获得了稳定的高能量全光纤结构2 m脉冲光纤激光器,脉冲重复频率在10~50 kHz之间可调,输出激光中心波长为1958 nm,输出脉冲宽度随着泵浦功率的增加不断减小,其变化范围为1.2~1.7 s。采用两级掺铥光纤放大器对种子激光进行放大,当脉冲重复频率为10 kHz时,获得了5.18 W的输出平均功率,输出脉冲宽度为1.6 s,单脉冲能量为0.518 mJ。