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The filter mechanism of a tunable filter with narrow-band in bulk semiconductor laser amplifier (SLA) is analyzed, which is suitable for dense wavelength division multiplexed (DWDM) optical fiber networks. The wavelength selectivity of the filter is derived from nondegenerate four-wave mixing (NDFWM) in semiconductor gain medium. It uses the direction of propagation to separate the desired wave-mixing product from the other light beams. The filters are shown to have very narrow passbands (subangstrom bandwidth) tunable over the entire semiconductor gain bandwidth. We gave the theoretical analysis of NDFWM effect in semiconductor gain medium is given and a set of nonlinear coupled wave equations is deduced, which are processed efficiently by Runge-Kutta method in numerical simulation. The influences of various structural parameters of the filter on the output bandwidth and efficiency were also discussed. 相似文献
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液晶法布里-玻罗滤波器可调谐特性分析 总被引:5,自引:5,他引:0
分析了液晶法布里-玻罗可调滤波器中介质反射镜反射相位引起的峰值波长漂移. 液晶法-玻滤波器通过外加电压调谐峰值波长, 反射相位会导致峰值波长漂移使器件不能达到DWDM系统的使用要求. 本文推导了一套计算反射镜反射相位的公式,将它应用于液晶法-玻可调滤波器的理论设计, 模拟结果定量表示了反射相位对峰值波长造成的影响. 这对确定液晶可调滤波器峰值波长和设计器件电驱动装置具有重要意义. 由此设计了一个在光通讯波段可单调调谐的液晶法-玻滤波器. 相似文献
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JIANG Yan CUI YipingTo whom correspondence should be addressed. PANG Shuming 《Chinese Journal of Lasers》1999,8(6):489-496
1 Introduction Today,withthequickdevelopmentofthehighdensewavelengthdivisionmultiplexing,thelinkcapacitywillbegreatlyenhanced.Alternatively,theenhancementofthelinkcapacitydependsontherelativelyhighwavelengthresolutionofthewavelengthfiltersintherecei… 相似文献
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基于遗传算法设计了斜边三角形光纤光栅(EFBG)的折射率调制函数;提出了光纤外径沿轴向变化、在拉应力下可获得可调谐的斜边三角形光纤光栅;计算分析了该器件多个物理参量对反射光谱的影响。在实验中,采用紫外激光扫描辐照方法,制备了短波边斜边带宽为0.7nm、反射率为96%的斜边三角形光纤光栅;采用程序控制氢氟酸腐蚀方法获得外径从原始62.5μm减小到45μm、在85mm长度内按设计要求变化的光纤光栅。对该光纤光栅施加从。到1.715N变化的拉力时,其反射光谱短波边的斜边带宽从0.7nm增加到2.3nm,实现了一种带宽大范围可调的斜边光纤光栅。 相似文献
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We apply liquid crystal on silicon (LCOS) in 0.8-$mUm standard complementary metal-oxide semiconductor (CMOS) technology to demonstrate a low-cost, high-performance pixelized liquid crystal variable optical attenuator (VOA) with pulse width modulation. We then build a prototype tunable filter by using this VOA along with a grating in the Littrow configuration. With the application of 5-V pulse width modulation, the proposed VOA achieves a 5.6-dB insertion loss, a dynamic range of more than 20 dB, a 50-GHz channel spacing capability, and a polarization-dependent loss (PDL) of less than 0.6 dB at 15-dB attenuation. Our VOA is suitable for applications such as dynamic channel gain equalizers, channel-blocking filters, sub-components of re-configurable add-drop modules, and wavelength selectors. 相似文献
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Particle penetrations through commercially available, electrically charged fibrous filters have been measured. The particles were monodisperse and in charge equilibrium. Tests were conducted for several particle sizes in the range 0.02 μm ≤ x ≤ 1 μm. The face velocity was varied in the range of 2 cm/s to 30 cm/s. The penetration has a bimodal dependence on particle size. This behaviour is not found for uncharged filters. The reduction in penetration and bimodal dependence is attributed to electrical collection effects. As the face velocity is increased, the electrostatic collection effects are significantly reduced. The results agree quantitatively with a model for particle penetration through charged fibrous filters recently presented in the literature by the authors. 相似文献
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We present the spot size dependence of dielectric multilayer filters for use in dense WDM systems. We found large dependences of filter performances on the spot size and the incident angle of input light, which should be important for miniaturizing multi-channel add/drop filters. 相似文献
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Victor G. Rivera-Llabres Kara N. Gentry Matthew Po Carlos M. Rinaldi-Ramos 《Particle & Particle Systems Characterization》2023,40(8):2300026
The size tunable formulation of magnetic alginate microparticles (MAMs) using a 3D flow-focusing microfluidic device is reported. The droplet phase consists of iron oxide nanoparticles (IONPs) in an alginate solution and the continuous phase consists of fluorocarbon oils. The stability of IONP colloids in alginate and calcium ethylenediamine tetraacetic acid solutions using optical microscopy, dynamic light scattering, and zeta potential measurements is studied. These studies suggest that IONPs coated with polyethylene glycol (PEG) are most stable. MAMs using the PEG-coated IONP colloid are then formulated and it is studied how MAM the average size and coefficient of variance vary as a function of droplet and continuous phase flow rates and viscosities. Droplet and MAM size decrease when the carrier flow rate or viscosity increases, and droplet and MAM size increase when droplet flow rate or viscosity increases. Crosslinking and drying of droplets result in MAMs whose diameter is ≈44% less than the original droplets while maintaining a population coefficient of variance below 8%. Conditions are identified that enable fabrication of MAMs with diameters between 30 and 60 µm with coefficients of variance of ≈6–7%. These results may guide future work exploring the role of MAM size on various applications. 相似文献
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T. Idehara N. Nishida K. Yoshida I. Ogawa T. Tatsukawa D. Wagner G. Gantenbein W. Kasparek M. Thumm 《International Journal of Infrared and Millimeter Waves》1998,19(7):919-930
The cavity of the newest gyrotron, Gyrotron FU IVA in the high frequency series of Fukui University gyrotrons (the Gyrotron FU series) is designed to minimize the mode conversion from the main cavity mode to the higher modes. In this paper, the experimental results are compared with simulations for the complete gyrotron oscillator. The gyrotron has an additional advantage to cover the wide frequency range in submillimeter wave region. 相似文献
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Wallace Kantor 《光谱学快报》2013,46(7):245-253
Experiments alleged to confirm the absolute speed of light by Sadeh, Fillipas and Fox, and those done at CERN on the emission of gamma rays by high speed particles are shown to be inconclusive. These experiments have been interpreted quantitatively on the basis of an “extinction” hypothesis formulated by J. G. Fox for which there is no experimental confirmation or denial. Rather than confirming the absolute speed of light, these null result experiments can also be regarded as merely showing the obliteration of the relative speed of light as it propagates through various media. 相似文献
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针对面对称高速飞行器滚转-偏航通道间存在的运动耦合、典型气动耦合和控制耦合,建立了耦合动力学模型,推导了耦合模态的数学描述;提出了基于滚转偏航/稳定比和副翼滚转/偏航操纵比的耦合模态分析方法,分析了副翼操纵对偏航通道的耦合影响程度;针对控制耦合引起的非最小相位特性,提出了基于偏航稳定力矩导数、副翼-偏航耦合力矩导数以及方向舵产生偏航力矩导数的控制耦合偏离边界条件,根据偏航稳定力矩导数、副翼-偏航耦合力矩导数的相对位置关系,确定控制耦合偏离区域,并分析了副翼控制滚转时的耦合失控特性.最后对失控特性进行了仿真验证,结果表明了耦合特性分析方法的有效性. 相似文献
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Abstract: Tunable diode laser absorption spectroscopy (TDLAS), as a noninvasive spectroscopic method, permits high-resolution, high-sensitivity, fast, in situ absorption measurements of atomic and molecular species and narrow spectral features in gaseous, solid, and liquid phases. Advances in new diode laser sources and laser spectroscopic techniques generally have triggered an increasing application of TDLAS in various disciplines (for example, atmospheric environmental monitoring, chemical analysis, industrial process control, medical diagnostics and combustion monitoring, etc.) over the last four decades. This article reviews some important developments in TDLAS, from its basic principles as a spectroscopic tool to the demonstration of gas absorption measurements, emphasizing signal enhancement and noise reduction techniques developed for improving current TDLAS performance. 相似文献
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Feasibility of Non-Collinear TeO2 Acoustic-Optic Tunable Filters Used in the Optical Communication 下载免费PDF全文
The characteristics and the structure of TeO2 acoustic-optic tunable filter used in communication are discussed briefly based on the acoustic-optic theory and it is shown that a large optical incident angle and a long interaction length are suitable for the optical add/drop multiplexer based on the TeO2 acoustic-optic tunable filter. The distribution of acoustic energy flow in the device supports the large optical incident angle. The long interaction length depends on the change of the device structure to some degree. The measured results of the samples show that the diffraction efficiency reaches at 96% in the tuning range larger than lOOnm and the bandwidth is about 2nm. It can be found that there is a good consistency with the basic theoretical mode. The optimized design result shows that the diffraction efficiency can arrive at 100%, and the bandwidth can be less than 0.4nm. Thus, the non-collinear TeO2 acoustic-optic tunable filter can play an important role in the coming general optical network. 相似文献
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Itoh Yoshifumi Lenggoro I. Wuled Okuyama Kikuo Mädler Lutz Pratsinis Sotiris E. 《Journal of nanoparticle research》2003,5(3-4):191-198
Highly crystalline, dense BaTiO3 nanoparticles in a size range from 30 to 360nm with a narrow size distribution (g = 1.2–1.4) were prepared at various synthesis temperatures using a salt-assisted spray pyrolysis (SASP) method without the need for post-annealing. The effect of synthesis temperature on particle size, crystallinity and surface morphology of the nanoparticles were characterized by X-ray diffraction and scanning/transmission electron microscopy. The nature of the crystalline structure was analyzed by Rietveld refinement and Raman spectroscopy. The particle size decreased with decreasing operation temperature. The crystal phase was transformed from tetragonal to cubic at a particles size of about 50nm at room temperature. SASP can be used to produce high weight fraction of tetragonal BaTiO3 nanoparticles down to 64nm in a single step. 相似文献