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光载超宽带脉冲雷达信号传输性能研究 总被引:2,自引:1,他引:1
采用双并行马赫曾德尔调制器产生高斯脉冲一阶微分和二阶微分型超宽带脉冲雷达信号和光载无线电传输技术,通过仿真研究了两种超宽带脉冲雷达信号在标准单模光纤中的传输特性.结果表明,高斯脉冲一阶微分型脉冲随着传输距离的增大而不断展宽,而高斯脉冲二阶微分型脉冲则先压缩后展宽.经100km标准单模光纤传输之后,在传输终端采用色散补偿光纤对传输信号进行不同程度的色散补偿,可获得满足美国联邦通信委员会规范要求的不同宽度高斯脉冲一阶微分和二阶微分型脉冲信号. 相似文献
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为解决检测面尺寸较大时CCD难以得到高质量数字全息图的问题,本文利用负透镜设计光学系统让CCD接收来自物体的缩小虚像,以球面波为参考波,使用单色CCD近距离得到三种色光照射下的大尺寸彩色物体的数字全息图,然后采用可控放大率波面重建算法得到同一尺寸的数字全息重建像,合成彩色数字全息重建像.同时,使用两种消零级方法去除零级干扰,提高重建像质量,一种方法利用空间光调制器相移技术在参考光中加入一次任意相移,记录两幅数字全息图,消除重建零级像|另一种方法使用“无干扰全息图”消除重建零级像及共轭像.本文讨论结果可为大物体彩色数字全息及多波长数字全息检测应用提供有益的参考. 相似文献
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弹光调制器(Photoelastic Modulator,PEM)互差频调制的新型偏振测量方法,能够同时实现三个斯托克斯光谱偏振参数测量,克服了现有方法的无法用阵列探测器有效采集,调制频率高的缺点,保留了原有弹光调制器偏振测量的优点。文章以光学系统的准单色光的偏振特性以及常用的偏振分析方法为基础,引入了Stokes矢量来表示入射光波的偏振特性。分析了弹光调制器实现偏振测量新方法的原理,利用三个弹光调制器工作在互相差异的频率上,对偏振光进行差频调制,产生载有偏振信息的低频分量,再通过锁相放大即可得到偏振信息,并给出利用MATLAB模拟仿真实现Stokes参量复原的过程。理论分析及仿真结果证明了该方法在理论上的可行性。 相似文献
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Polarisation-insensitive strip-loaded waveguide for electro-optic modulators and switches 总被引:1,自引:0,他引:1
Jie Sun 《Optics Communications》2009,282(11):2255-2258
A polarisation-insensitive electro-optic (EO) waveguide consisting of a dye-doped TiO2/SiO2 slab and a SU-8 strip-loaded rib is designed and fabricated. By optimizing the refractive index and size of waveguide, a trade-off between polarisation-insensitive condition and large EO efficiency (optical field interaction with the EO material) is obtained. The average transmission loss of the waveguide is less than 2.0 dB/cm. A Mach-Zehnder (M-Z) interferometer intensity modulator based on this waveguide with excellent poling stability is fabricated and measured, exhibiting 7 V half-wave voltage with 1.8 cm EO interaction length and 2.7 cm total length. This strip-loaded structure is proved to be a valuable application in EO modulators and switches. 相似文献
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This paper demonstrates an alternative electrode structure for low power optical modulation based on a slotted waveguide geometry filled with E-O polymers. A reverse-biased p?n junction is constructed inside the slot waveguide for apply modulation voltage. With this structure, the fabrication tolerance of the slot based E-O modulator should be more flexible. Analysis shows that the modulation speed of our design is comparable with the through-etched slot modulator, at the level of picoseconds. 相似文献
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由节点开关单元按照一定的连接规则所构成的光互连网络,在全光通信和光信息处理中具有重要的应用。基于节点开关一般实现光信号的直通和交换功能的特点,利用成熟的偏振光控制技术,通过位相型空间光调制器对信号光偏振态的控制,完成信号的路由和开关动作,从而设计出具有直通、交换、上播和下播功能的节点交换开关。与传统设计思想相比,该方法不仅能够充分利用信号光的能量,有效的减少光能量的损耗,而且还具有与偏振无关等特点。该四功能交换开关,对于优化和拓展光互连网络的结构和功能具有一定的意义。 相似文献
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Ram Prakash Dwivedi 《Optics Communications》2011,284(5):1418-1423
We report, for the first time, on the design of a plasmonic modulator working on the principle of the elasto-optic effects in a directional coupling structure, utilizing three parallel metal-dielectric-metal waveguides. We propose to achieve the active switching of the power propagation using the elasto-optic effect and optimize the extinction ratio of the optical modulation. The device is characterized and numerically analyzed using the finite-element-method at the wavelengths of 1.55 μm. For the modulator length of 2.33 μm, the extinction ratio of the modulation is nearly 14 dB, and the calculated attenuation loss is 4.5 dB. The calculated driving voltage is 4.8 V for the given modulator. The effect of the applied voltage on the modulation is also analyzed. 相似文献
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An analytical model of a super linear optical modulator with high spurious-free-dynamic-range (SFDR > 130 dB) is presented and analyzed. The linear modulator is referred to as IMPACC which stands for Interferometric Modulator with Phase-modulating And Cavity-modulating Components. The modulator is based on a unique combination of a RF-driven phase-modulator (PM) and a ring resonator (RR) within a Mach-Zehnder interferometer (MZI) configuration. Our analysis shows that our design can achieve SFDR values which are ~ 20 dB higher than the standard MZI modulator and 3-5 dB from the Ring Assisted Mach-Zehnder Interferometer (RAMZI) modulator. Both PM and RR in the IMPACC are simultaneously driven by a RF signal of the same frequency, but not necessarily the same amplitudes. The analytical model shows that the combination of these two optical elements, with the proper choice of RF-driving and device parameters, can lead to four important and compelling consequences. First, it offers a wholistic and elegant model in which the standard MZI modulator and the RAMZI modulator are just special cases of IMPACC. Second, the model offers an excellent parameter optimization methodology for fast parameter (internal and/or external) selection and performance evaluation. Third, it provides additional degree of control through the introduction of an external control parameter, the RF power split ratio (F). Lastly, it demonstrates one unique feature of IMPACC such as adaptive SFDR characteristics, where manufacturing tolerances in the transmission coefficient (τ) of the RR can be compensated with proper adjustments of the external parameter of the power split ratio (F). 相似文献