Design and Analysis of the Integrated Plasma Wave Micro-Optical Modulator/Switch

Feasibility of a new integrated amplitude modulator/switch operating up to the visible spectrum, based on the absorption of light due to the linear interaction of the incident laser and a two-dimensional plasma layer is demonstrated. Plasma layers are generated via the Muller effect at the waveguide's interfaces. A plasma wave is excited in the two-dimensional gas when it is illuminated by electromagnetic radiation. Thus, due to the energy transfer from the electromagnetic wave to the plasma wave, the output light intensity can be controlled. The device is capable of amplitude modulation of guided beams in dielectric waveguides. Analysis based on both full-classical and semiclassical approaches are performed and are compared.     

A novel wavelength shift keying transmitter using a pair of Mach-Zehnder modulators

A novel and simple method to achieve wavelength shift keying (WSK) modulation is proposed and experimentally demonstrated. The proposed WSK transmitter consists of a pair of Mach-Zehnder modulators (MZMs) that are biased appropriately to achieve complementary operation. When a non-return-to-zero data stream is applied to the two MZMs, thanks to the complementary operation of the MZMs, the WSK-modulated signal can be obtained by combining the two intensity-modulated optical signals. A tunable optical delay line (ODL) is applied to achieve synchronization between the two optical signals. The ODL can also be used to compensate for the dispersion-induced walk-off effect between the two optical carriers. The application of the proposed WSK transmitter in a passive optical network is demonstrated, in which the downstream WSK signal is reused as optical carrier for upstream intensity-modulated data transmission. The proposed approach is experimentally realized; experimental results verify the feasibility of the approach.     

基于空间光调制器的HDR图像获取方法

提出一种利用空间光调制器对物方光线进行调制并多次曝光的方法来获取HDR图像.讨论了该方法的原理,并根据原理搭建实验装置进行了实验.实验装置中以LCOS作为空间光调制器,以CMOS作为成像传感器,通过多次曝光获得系列图像,利用图像合成算法生成HDR图像.该方法具有实时性好、扩展性强、成本较低等优点.     

光电混合机器人视觉系统中光寻址空间光调制器的噪音处理

分析了光寻址空间光调制器对连续图像采样产生的噪音和假频,利用采样理论,提出设置光学去假频前置滤波器抑制噪音和假频的方法.理论分析得出去假频前置滤波器为矩形窗函数的基础上,根据视觉系统中光寻址空间光调制器的参量,计算出了本系统所用的去假频前置滤波器的结构尺寸.视觉系统图像特征提取试验结果表明效果良好.     

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ECRH阳极高压电源系统由高压直流电源及调制器两部分组成。高压直流电源采用晶闸管调节升压变压器的输入电压,在低电位端利用三极管串联线性调整输出DC电压,控制器采用了内外双闭环控制技术,其最大输出为30kV/130mA;调制器使用真空四极管为核心部件。使用仿真软件对电路进行了优化设计。独立调试实验及HL-2A装置放电实验数据表明,该电源系统具有大范围调压、低纹波输出、快速调制等特点。     

液晶电视空间光调制器对比度的研究

本文分析了影响液晶显示屏对比度的种种因素,根据偏振光在液晶中传输的性质,提出了一种有效改进液晶电视空间光调制器对比度的新方法。通过实验得到了液晶电视最佳对比度的条件,从而使原来4∶1的最佳对比度提高到19∶1。     

Si2N2O基体铌酸锂调制器有限元法研究

提出一种新型基于Si2N2O基体的LiNbO3行波调制器,利用有限元方法对该调制器进行数值分析并获得调制器的优化结构尺寸.该新型调制器带宽达到120 GHz,半波电压为3.5 V,特性阻抗为50.2 Ω.结果表明该调制器具有大的调制带宽和良好的阻抗匹配,在未来光通信中具有很好的应用前景.     

高准确度光纤陀螺中相位调制的控制研究

在相位调制器基础上,提出了围绕干涉型光纤陀螺的闭环控制方案.对高准确度光纤陀螺中Y波导集成光学器件的调制特性及系统测试方法进行了研究,对其应用及光路各环节配合的技术进行了探讨,对该器件在光纤陀螺系统中的特性和测试系统进行讨论.在高准确度光纤陀螺中取得明显效果.目前,工程样机的零偏稳定性已达到0.02°/h.     

线性、径向和环向偏振飞秒激光诱导非晶合金周期性表面结构

研究在复杂偏振条件下,飞秒激光诱导非晶合金Zr44Ti11 Cu10Ni10Be25(at％)表面周期性结构的形成机理.实验采用波长800 nm、脉宽120 fs的超短脉冲激光,分别在线性、径向、环向偏振条件下,诱导非晶合金表面生成复杂的周期性表面结构.表面结构由周期为652～723 nm的低频条纹和周期为1 304～1 765 nm的微型条纹组成.通过有限差分时域法仿真分析,发现微型条纹由粗糙表面引起的定向调制的表面散射电磁波与入射激光干涉形成.仿真结果与实验结果一致,验证了微型条纹形成机理的有效性.     

Porphyrin Supramolecule as Surface Carrier Modulator Imparts Hole Transporter with Enhanced Mobility for Perovskite Photovoltaics

Modulating the surface charge transport behavior of hole transport materials (HTMs) would be as an potential approach to improve their hole mobility, while yet realized for fabricating efficient photovoltaic devices. Here, an oxygen bridged dimer-based monoamine Fe^III porphyrin supramolecule is prepared and doped in HTM film. Theoretical analyses reveal that the polaron distributed on dimer can be coupled with the parallel arranged polarons on adjacent dimers. This polaron coupling at the interface of supramolecule and HTM can resonates with hole flux to increase hole transport efficiency. Mobility tests reveal that the hole mobility of doped HTM film is improved by 8-fold. Doped perovskite device exhibits an increased efficiency from 19.8 % to 23.2 %, and greatly improved stability. This work provides a new strategy to improve the mobility of HTMs by surface carrier modulation, therefore fabricating efficient photovoltaic devices.