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普通单模光纤中光孤子传输问题的研究 总被引:1,自引:0,他引:1
在使用普通单模光纤的光孤子传输系统中,放大器自发辐射(ASE)噪声和色散波逸出是限制光孤子传输的两个主要因素,它们将引起孤子能量科动和定时抖动,从而导致系统误码。本文分别研究了带限光滤波器对ASE噪声的抑制和非线性增益对色散波的抑制以及对孤子传输系统的稳定作用,并设计了使用普通单模光纤的光孤子传输系统。 相似文献
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多扰动影响下的滤波控制色散管理孤子系统 总被引:1,自引:0,他引:1
为了分析和抑制色散管理孤子在长距离、多信道系统中传输存在的多种扰动因素,采用变分法解析了信道放大自发辐射噪声、信号间串扰等多种因素对系统的影响,研究了在线滤波器控制色散管理孤子的频率漂移和定时抖动的能力。结果表明,合理优化配置滤波器与色散管理孤子参数能够稳定色散管理孤子幅度和脉宽参数,抑制各个扰动对系统的影响,其中以交叉相位调制-自发辐射扰动减低最为明显,然后分别是自发辐射噪声和交叉相位调制。这种最佳的滤波选择方案能为估计高速大容量系统传输性能提供参考。 相似文献
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光纤中具有轻微的非线性和一定的色散特性,这两种特性分开来说,将会损害光纤通信中系统的性能,但是在一定的条件下,这种小的非线性的影响可以抵消色散的影响,产生孤子.在无耗的光纤介质中,孤子可以传输任意距离而不改变形状.实际的有耗光纤中,为了使用孤子,用光放大器来抵消光纤的损耗,以维持链路上孤子能量的稳定.通常在光纤中非线性和色散效应都比较弱,对光纤的作用表现为两种效应的相加性.放大器的自发辐射噪声(ASE),通过两种不同的机理增加了系统的误码率(BER):(1)通常的加性噪声的影响;(2)孤子速度的抖动.第二种效应导致脉冲到达时间的抖动,这就是Gordon-Haus效应.由于光纤存在损耗,光孤子在光纤里的传输过程中,其幅度随传输距离按指数规律衰减,必须对孤子能量进行放大.一种是分布式光放大器方法;另一种是集总式光放大器方法.分布式EDFA使用低浓度的掺铒光纤作为传输介质.集总式放大就是在光纤线路中每隔一段距离L接入一段集总式光纤放大器(目前通常采用EDFA)来补偿孤子能量的损失.本文研究了孤子传输在存在损耗和放大器自发辐射噪声(ASE)时的孤子传输方程及其解.并对孤子传输的控制作了概述.(PD3) 相似文献
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利用啁啾光纤光栅(CFBG)串联的多波长色散补偿器对长距离传输的8个信道信号进行色散补偿,各个信道波长符合ITU-T标准,波长间隔为100 G.系统采用掺Er3+光纤放大器(EDFA)作为功率放大器,在2 015 km的G.652光纤上无前向纠错(FEC)无电中继实现8×10 Gb/s零误码传输.结果表明,利用CFBG构成的色散补偿器各信道补偿一致性好,CFBG不但能通过滤除带外噪声有效减小长距离传输中由放大器产生的自发辐射噪声(ASE)的积累,提高传输信号的信噪比(OSNR),而且其较低的非线性特性有利于抑止信号劣化,从而有效提高长距离波分复用(WDM)的传输性能,扩展无电中继传输距离. 相似文献
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采用变分法讨论了放大器噪声对色散管理光孤子脉冲参数的影响。讨论了ASE噪声对脉冲相位、脉冲中心时间和中心频率的影响,并且对比讨论了采用密集色散管理系统和降低平均色散值后,ASE噪声对脉冲的影响,结果表明:密集色散管理孤子系统和平均色散接近于零的色散管理系统更有利于降低放大器噪声对脉冲的扰动。 相似文献
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S波段分布式光纤拉曼放大器的实验研究 总被引:3,自引:0,他引:3
在S波段对3种不同配置的色散补偿型分布式光纤拉曼放大器(FRA)进行了研制。实验证明:5km DCF-50km G652光纤色散补偿型分布式FRA的增益和噪声特性优于50km、G652-5km DCF光纤和25km G652-5km DCF-25km G652光纤色散补偿型分布式FRA。测量了5km DCF-50km G652光纤色散补偿型分布式FRA的增益光谱和噪声谱。存DWDM光纤传输系统中,色散补偿分布式FRA对S波段1520nm光谱波段2个光谱间隔为0.262nm(频率间隔为34.1GHz)信号信道光谱的传输特性优于50km G652正色散FRA和5km DCF负色散FRA。 相似文献
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聚对苯撑苯并双(口恶)唑发光及其器件制备 总被引:2,自引:0,他引:2
采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加. 相似文献
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在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65~4GHz的频带内隔离深度可达-40~75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证. 相似文献
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Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years. 相似文献
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C. Fulk R. Sporken J. Dumont D. Zavitz M. Trenary B. Gupta G. Brill J. Dinan S. Sivananthan 《Journal of Electronic Materials》2005,34(6):846-850
We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron
spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations.
It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311)
had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy,
while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge
site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging
atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites.
This would ensure a nonpolar, B-face growth. 相似文献
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光子晶体微腔发光二极管 总被引:1,自引:0,他引:1
光子晶体微腔因其具有增强自发辐射、定向输出和单模工作的能力而受到广泛关注。介绍了光子晶体微腔发光二极管的基本原理、设计、特性、制作及其典型器件。 相似文献
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The power generation demand is increasing day-by-day throughout the world, therefore, the use of hybrid systems becomes a significant solution. The hybrid renewable energy system (HRES) is used for delivering power in various regions in order to overcome intermittence of wind and solar resources. Because of increasing environmental problems, for example, greenhouse gas emission and energy cost have interested novel research into substitute methods in favour of electrical power generation. Maximum Power Point Tracking (MPPT) control method is a vast deal of novel research used for enhancing the efficiency of HRES. The authors have revealed that the hybrid techniques i.e. Global MPPT, fuzzy-neuro systems, Adaptive Neuro-Fuzzy Inference System (ANFIS), Perturbed and Observe (P&O) + Adaptive Neural Network (ANN) etc. can provide best results as compared to other MPPT control methods. This paper offering a state of art review of MPPT control techniques for HRES. 相似文献
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多孔硅发光机制的分析 总被引:4,自引:0,他引:4
从量子力学的基本理论出发讨论了量子限制效应,推导出多孔硅有效禁带宽度增量并用量子限制效应和表面态及其物质在发光中作用的理论解释了PS光致发光的实验现象。 相似文献
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级联多个循环冗余校验(CRC)的LDPC译码算法有效地改善了译码的收敛特性。然而在其译码算法中,当CRC检测的整体漏检概率不够低时,出现误码平台。因此,该文提出了改进算法,通过减少在译码算法中CRC检测的次数,降低整体漏检概率,提高了误码性能。仿真表明改进的算法提高了误码性能,译码复杂度也增加不大。 相似文献
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Roskowski A. M. Preble E. A. Einfeldt S. Miraglia P. M. Davis R. F. 《Journal of Electronic Materials》2002,31(5):421-428
High-resolution x-ray diffraction (XRD) and atomic force microscopy (AFM) of pendeo-epitaxial (PE) GaN films confirmed transmission
electron microscopy (TEM) results regarding the reduction in dislocations in the wings. Wing tilt ≤0.15° was due to tensile
stresses in the stripes induced by thermal expansion mismatch between the GaN and the SiC substrate. A strong D°X peak at
≈3.466 eV (full-width half-maximum (FWHM) ≤300 μeV) was measured in the wing material. Films grown at 1020°C exhibited similar
vertical [0001] and lateral [11
0] growth rates. Increasing the temperature increased the latter due to the higher thermal stability of the GaN(11
0). The (11
0) surface was atomically smooth under all growth conditions with a root mean square (RMS)=0.17 nm. 相似文献