共查询到19条相似文献,搜索用时 93 毫秒
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偏振态调制的偏振无关干涉型光纤传感器 总被引:2,自引:0,他引:2
针对低双折射光纤双束干涉型传感器的两臂偏振态随机变化引起的信号衰落提出了一种新型的光纤传感器结构。通过在双束干涉仪的一臂中加入适当的对光波偏振太的高尖三角波或正弦波调制的偏振制,可以在干涉中见度略有降低的情况下消除偏振衰落的影响,实现偏振无关的干涉型光纤传感器。 相似文献
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介绍了光纤Mach-Zehnder(MZ)干涉仪系统的结构.给出了光纤Mach-Zehnder干涉仪系统中信号光与参考光的干涉原理以及影响干涉光强的因素.同时也分析了光纤耦合器的交叉耦合,另外也给出了PZT的作用.阐述了光纤偏振控制器的结构、工作原理及其对光纤Mach-Zehnder干涉仪系统传感臂偏振态的控制,最后给出了光纤Mach-Zehnder干涉仪系统的应用. 相似文献
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偏振诱导信号衰落现象的抑制是干涉型光纤传感系统的关键技术之一. 针对法拉第旋镜(FRM)法抑制偏振诱导信号衰落技术的残留偏振相位噪声问题进行了深入的理论和实验研究. 运用琼斯矩阵法建立了基于法拉第旋镜的干涉型光纤传感系统偏振相位噪声的理论模型; 分析了影响系统偏振相位噪声的主要原因: 法拉第旋镜的旋光角度偏差、入射光偏振态调制度、干涉仪两臂光纤双折射; 提出了相应的抑制偏振相位噪声的方法. 详细仿真分析了入射光偏振态调制度对干涉型光纤传感系统偏振相位噪声的影响, 仿真分析得出若法拉第旋镜旋光角度偏差为最大工艺制造误差1°, 当入射光偏振态调制度为1.84 rad时, 系统可能出现的最大偏振相位噪声为0.0815 rad. 最后, 搭建了基于M-Z型偏振态调制器的偏振相位噪声测试系统, 测试了在传输光纤受到外界偏振扰动的情况下, 干涉传感系统存在的偏振相位噪声, 实验测试结果与理论分析结果基本一致, 有力地证明了该偏振相位噪声理论分析模型的正确性. 相似文献
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干涉型光纤传感器的消偏振衰落技术研究 总被引:1,自引:0,他引:1
本文对消除干涉型光纤传感器信号偏振衰落的偏振分集接收PDR(Polarization Diversity Receiver)技术进行了理论分析.通过三态PDR方式,对输出的最大有效幅度信号进行选取,能够避免传输光偏振态变化导致干涉信号完全衰落的现象,使干涉信号有效幅度在一定范围内变化.采用基于反正切计算的相位生成载波PGC(Phase Generated Carrier)解调技术的相位测量结果不受由于偏振衰落导致干涉信号有效幅度变化的影响.提出结合三态PDR方式和基于反正切计算的PGC解调技术消除偏振衰落问题的影响,实现干涉型光纤传感器中相位信号的理想解调. 相似文献
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干涉型光纤传感器及阵列的分集检测消偏振衰落技术的研究 总被引:4,自引:0,他引:4
对干涉型光纤传感器的分集检测消偏振衰落技术进行了新的理论分析,提出了将各种信号平方后相加的信号处理方式,使之能实现单元及阵列的实时消偏振衰落信号检测。计算了这一信号处理方式可能引起的幅度最大波动,并得出三路检测偏是分集检测的一个合适取值的结论。根据理论分析,在马赫-陈德尔干涉仪上进行实验研究取得了较好结果,并设计了用于阵列的分集检测实现方式。 相似文献
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基于差分编码方式提出一种改进方案.在Alice端用光纤马赫-曾德干涉仪产生双脉冲差分信号;在Bob端,用双法拉第反射式麦克尔逊干涉仪代替光纤马赫-曾德干涉仪,这种干涉仪能自动补偿环境引起的偏振抖动和光纤双折射引起的相位漂移,从而提高系统稳定性.双协议(即双脉冲差分协议联合BB84协议)的使用,增强了系统的安全性.该系统具有高效、安全、简洁、稳定等优点,在实验上实现了长期稳定的密钥分发和量子保密通信,误码率<5%,传输距离达80km. 相似文献
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干涉型光纤传感器阵列的偏振态反馈叠加控制 总被引:1,自引:0,他引:1
提出了在干涉光纤传感器阵列中将各传感器的最佳输入偏振态反馈控制信号叠加用于阵列最佳输入偏振态控制的方案,并对阵列各单元最佳输入偏振态的较差分布时的控制效果进行了理论分析,对达到这一较差分布的概率也进行了计算,分析表明,该方案简单易行,经过信号处理能使各个光纤传感器在降低信噪比的情况下吏可见度均达最大值1,从而消除了阵列中各单元的偏振态衰落。 相似文献
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The case of excitation of nuclear quadrupole resonance (NQR) in nitrogen-containing compounds is examined for significant
sample removal under conditions of strong dispersion of the registered signal. Principal limitations on the sensitivity of
remote NQR observations are demonstrated. A method of registering resonant lines after fading of the main signal is suggested.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 8–11, August, 2008. 相似文献
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G. B. Soifer 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(5):765-769
The activation energy of thermoactivated molecular motions in solids is determined by examining the influence of these motions
on the temperature dependence of the nuclear quadrupole spin-lattice relaxation rate and quadrupole resonance (NQR) signal
intensity for chlorine-35. In the latter case, the heating of the crystals is accompanied by the fading of resonance signals,
which is analyzed using a linear correlation between the activation energy of this motion and the fade-out temperature. The
correlation parameters are demonstrated to be dependant on the type of molecular motion. The relaxation method is shown to
be more effective in studying molecular motion and evaluating its activation energy as compared to the NQR signal fading technique. 相似文献
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Effects of atmospheric turbulence and building sway on optical wireless-communication systems 总被引:1,自引:0,他引:1
Arnon S 《Optics letters》2003,28(2):129-131
Urban optical wireless communication (UOWC) systems are considered a last-mile technology. UOWC systems use the atmosphere as a propagation medium. To provide a line of sight the transceivers are placed on high-rise building. However, dynamic wind loads, thermal expansion, and weak earthquakes cause buildings to sway. These sways distort the alignment between transmitter and receiver, causing pointing errors, the outcome of which is fading of the received signal. Furthermore, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received signal, resulting in impaired link performance. A bit-error probability (BEP) model is developed that takes into account both building sway and turbulence-induced log amplitude fluctuations (i.e., fading of signal intensity) in the regime in which the receiver aperture, D0, is smaller than the turbulence coherence diameter, d0. It is assumed that the receiver has knowledge about the marginal statistics of the signal fading and the instantaneous signal-fading state. 相似文献
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针对可调谐半导体激光吸收光谱一次谐波信号中具有背景信号及较大的基线信号,提出一种新型的背景消除与基线校正的处理方法.分析了一次谐波背景中的激光器相关强度调制信号,电子学噪声和光学干涉条纹,采用无吸收谱线区域检测谐波方法消除背景信号.给出了激光器不同工作温度时的电流和强度之间的关系曲线,由此设计出消除背景后剩余基线的校正方法.文中给出了背景搜索方法的原理以及LabView软件流程图.设计了检测氟化氢气体的实验系统,根据谱线选取原则确定吸收谱线为1312.59 nm,设置激光器的工作温度为27.0?C,对应的背景温度为30.2?C.一次谐波信号经过背景消除和基线校正后,信号的畸变得到明显改善,基线得到校正,验证了该方法在激光器其他工作温度(26.7—27.2)是有效的,并对HF气体浓度精度的改善进行了定量分析,为一次谐波信号的后续处理提供了方便. 相似文献
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提出了一种新型的干涉型光纤传感器阵列的消偏振衰落技术。在时分复用系统中,在全保偏传感基元的基础上,使用单模光纤做传输光纤搭建系统,通过对输入偏振态进行高频调制,能够在光强有所下降的情况下较好地解决了系统的偏振衰落问题。理论分析证明,当EOM相位调制的初相位设置为π/4,采样率和相位调制频率设置恰当时,通过PGC内调制解调技术可实现消偏振衰落。在理论分析的基础上进行了MATLAB软件模拟,解调出来的信号与原始信号基本重合。 相似文献
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A new layered space--time detection algorithm for frequency selective fading multiple-input multiple-output channels based on particle filter 下载免费PDF全文
In this paper, a new observation equation of non-Gaussian frequency
selective fading Bell Labs layered space time (BLAST) architecture
system is proposed, which is used for frequency selective fading
channels and non-Gaussian noise in an application environment of
BLAST system. With othogonal matrix triangularization (QR
decomposition) of the channel matrix, the static observation
equation of frequency selective fading BLAST system is transformed
into a dynamic state space model, and then the particle filter is
used for space--time layered detection. Making the full use of the
finite alphabet of the digital modulation communication signal, the
optimal proposal distribution can be chosen to produce particle and
update the weight. Incorporated with current method of reducing
error propagation, a new space--time layered detection algorithm is
proposed. Simulation result shows the validity of the proposed
algorithm. 相似文献