磁致伸缩光纤磁光光学双稳态

报道了一种基于磁致伸缩原理实现的全光纤结构磁光光学双稳态装置。与分立元件的磁光双稳系统相比较，该系统的双稳开关功率降低了２～３个数量级，实验结果与理论计算相符。     

磁熵变测量实验装置

简述了磁熵概念及磁熵变测量原理,介绍了应用于教学的磁熵变测量实验装置.利用该装置测量了金属钆在0～50℃温度范围,最大磁场为2T的等温磁化曲线,计算了不同温度下的磁熵变.     

适用于超高灵敏磁测量的新型高效磁屏蔽研究

高效磁屏蔽对于超高精度超导量子干涉仪(SQUID)等超高灵敏器件可靠稳定工作至关重要。实践中一般采用多层的高磁导率笨重复合磁屏蔽,或者用小型的轻量屏蔽桶配合差分式平面梯度计完成超高灵敏信号测量。文章作者提出并实现了一种新型的高性能磁屏蔽装置,采用实时的动态磁补偿与高温超导线圈相结合就可以实现。对该装置磁屏蔽效果进行了数值仿真计算,并实际测量了该屏蔽装置的轴向和横向磁场,装置屏蔽因数最高可达80 dB;实验测量发现,新型装置可以同时有效地屏蔽轴向与纵向磁场干扰。     

磁热效应演示装置的设计与制作

介绍了磁热效应演示装置的工作原理及设计方案,将磁热材料Mn1.28Fe0.67P0.48Si0.54作为磁工质对样机进行测试,实验结果与文献值相比基本一致.通过重复测试验证了演示仪的可靠性.该装置因其结构简单、便于操作、测量用时短、成本低廉等优点,为磁热效应的研究提供了补充测量手段.     

折射率调制型光纤传感器在溶液浓度测量中的应用

本文详细报道了用折射率调制型光纤传感器测量溶液浓度的原理及实验装置。为了消除光源光强的不稳定性对测量精度提高的影响,我们提出用光学双稳态装置稳定光源的输出功率并将它用于实际测量中,实验结果表明:本方法用于测量溶液的浓度在灵敏度、精度和稳定度方面都有较大的提高,并且可用于在线监测。     

基于磁致旋光效应的光双稳态装置

基于磁致旋光效应构建磁光混合型光双稳装置对光学双稳态展开研究,传统装置的调制系统工作电压一般在1 000～3 000V,需要在高压屏蔽条件下才能操作,而本装置的调制系统的工作电压仅为10V左右,极大的增加了实验的简便性和安全性.在此基础上探究了初始偏置宗量和平均输入信号等系统参量对光双稳装置工作性能的影响,并经过比较发现初始偏置宗量与临界值相差5°左右,平均输入信号为12～18mV时,光双稳装置工作性能较高.     

磁探针参数的标定

为了标定EAST装置电磁测量系统中的磁探针位置偏差和回路增益,通过分析该装置中的误差源,设计了极向场线圈的通电模式。运用格林函数等算法程序对测量数据进行预处理,利用简化的泰勒线性展开,结合带权重的最小二乘法对数据进行多次循环迭代,拟合出磁探针的位置偏差和回路增益。实验结果表明,使用该方法标定是合理的。     

EAST装置的磁探针设计

介绍了EAST装置中磁探针设计中的结构、安装位置、匝面积的标定、幅频响应,并给出了该磁探针的标定误差和Mirnov线圈幅频响应特征图。两轮EAST放电试验表明,电磁测量的信号满足装置运行和等离子体控制的需要。     

HL-2M 装置磁测量积分器设计

在核聚变实验中, 积分器是还原微分信号的基本手段,低漂移积分器系统的研制是托卡马克实验中 的重要环节。介绍了用于 HL-2M 装置磁测量的低漂移积分器系统。通过模拟与数字补偿相结合的方法减小漂移, 提高了信号间的测量精度。性能测试显示,积分器输出漂移小于 2mV/15s,积分时间常数精度优于 0.3%。该积分 器应用于 HL-2M 装置实验,满足磁测量系统的测量需要。     

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为了标定EAST装置电磁测量系统中的磁探针位置偏差和回路增益,通过分析该装置中的误差源,设计了极向场线圈的通电模式。运用格林函数等算法程序对测量数据进行预处理,利用简化的泰勒线性展开,结合带权重的最小二乘法对数据进行多次循环迭代,拟合出磁探针的位置偏差和回路增益。实验结果表明,使用该方法标定是合理的。     

Simple semi-analytical model for bistable cross-gain modulation in quantum dot VCSOAs

A novel semi-analytical model for cross-gain modulation (XGM) in quantum dot vertical-cavity semiconductor optical amplifier has been derived. The derived model, which is simple, requires small computational time compared with numerical simulation and can efficiently be used to investigate the optical bistable/stable characteristics of the device. Large XGM bandwidth can also be obtained when the device operates in the bistable region and in the stable region close to the bistable edge. A figure of merit is proposed to optimize the complicated tradeoff between the XGM bandwidth, efficiency, applied current and the input pump to probe ratio. We find that optimum characteristics can be obtained in our investigated device when the probe wavelength is detuned by 9 Å above the resonant wavelength and when a specific CW probe density is applied to the input of the device.     

A bistable liquid crystal electro-optic modulator

A new liquid crystal hybrid bistable optical device is described. Optical bistability has been observed and the use of this device for optical logic elements and ultralinear modulation applications demonstrated. The transient response of the device for optical logic elements and ultralinear modulation applications demonstrated. The transient response of the device has also been studied and a “critical slowing down” phenomenon observed.     

Semiclassical theory of optically bistable laser by output-feedback pumping scheme

Steady-state solutions of the output-feedback pumped bistable laser(OFPBL)have been obtained using the semiclassical laser equations.A linear-stability of the solutionshas been analysed.The results tell us that width of the hysteresis loop and the laser output in-tensity vary widely with the pump intensity and the intensity of input optical signal and thefeedback coefficient of the laser output as well as the other parameters.It shows that this typeof bistable laser is a kind of active optical bistable device which can be adjusted and controlledconveniently.     

Transients in all-optical bistability using transverse optical pumping: Observation of critical slowing down

We report on the transient response of an all-optical bistable device to step-inputs of light. The nonlinear mechanism used for bistable switching relies on transverse optical pumping within the Zeeman sublevels of the sodium ground state. Our measurements demonstrate the crucial role of critical slowing down for switching time. We also find that time-dependent diffusion processes can strongly affect the dynamics of this bistable device. Numerical calculations are shown to yield results in satisfactory agreement with experimental data.     

一种光电混合集成有源光双稳器件

本文报道一种光电混合集成的有源双稳态器件,它仅由一只半导体激光器,两只PIN光电探测器及几只电子元器件构成.实验上得到了光学迟滞回线,显示了光开关、光存储、光脉冲整形等功能.文中简述了器件工作原理,光电混合集成制作工艺技术及性能指标.     

ZnS光学双稳性器件中的不稳定性

本文首次报道ZnS干涉滤光片双稳器件中的自再生脉冲现象,并对器件产生这一不稳定性的条件和过程进行了分析及模拟计算,该器件有可能作为光学脉冲发生装置用于数字光计算研究,演示了光计算回路的逻辑功能.     

Electrical bistability of tris-(8-hydroxyquinoline) aluminum (Alq3)/ZnSe organic-inorganic bistable device

We present that the electrical bistability in organic-inorganic bistable devices based on tris-(8-hydroxyquinoline) aluminum (Alq₃) and zinc selenide (ZnSe) with the tri-layer structure of Alq₃/aluminum (Al)/ZnSe. The current-voltage characteristics of the bistable device exhibit two electrical states as low (OFF state) and high (ON state) conductivity with ON/OFF ratio about four orders of magnitude. The conduction mechanisms in both ON and OFF states were analyzed by theoretical model. In the OFF state, the conduction mechanisms can be explained by thermionic emission model, which the ON state can be described by ohmic conduction model. The retention times of both states are more than 8000 s, and the device can reproduce continuous write-read-erase-read switching cycles. Moreover, for the organic-inorganic bistable device was kept at one year in ambient condition without encapsulation. The device still exhibited the electrical bistable behavior. Consequently, the ZnSe layer may be led to improve the lifetime property of the bistable device which acted as a self-encapsulating layer.     

有源半导体双稳放大器稳定性分析

本文从半经典理论出发,对有源双稳放大器进行了稳定性分析,其结果表明:有源双稳器件远较无源器件易产生正沿不稳定性。在此基础上,我们讨论了有源E-P型双稳开关器件的实用开关速度的极限,实验中我们采用两个InGaAsP/InP双异质结单纵模激光器观察到了全光型开关现象。     

Opto-electronic bistable devices in real-time optical information processing

An opto-electronic bistable device using a twisted nematic liquid crystal cell is described. The optical bistability characteristics of this device are used in a new liquid crystal light valve with bistability in cellular array structure. Experimental studies demonstrate the applications of such opto-electronic bistable devices in real-time optical information processing such as intensity limiting for contrast improvement and noise elimination, edge enhancement for pattern recognition, linear and nonlinear optical filtering (in spatial and spectral domains).