共查询到18条相似文献,搜索用时 125 毫秒
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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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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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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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Interferometric optical fiber sensor relies on the coherent mixing of two optical signals, which is strongly polarization dependent. The fluctuation in the input polarization to an interferometric optical fiber sensor can result in not only the variation of the visibility but also the generation of excess phase noise in the output. In this paper, the relationship between the visibility and polarization-induced phase noise coefficient is described and theoretically confirmed. The use of tri-state polarization diversity receivers to eliminate polarization-induced signal fading and reduce phase noise is theoretically and experimentally demonstrated. The result shows that tri-state PDR that improves the visibility can reduce the polarization-induced phase noise and the signal can be correctly demodulated. 相似文献
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针对单模光纤干涉仪两臂中光的偏振态受环境变化引起的信号衰落,提出了一种新的消偏振衰落方案.该方案基于单臂光纤干涉仪,通过对干涉仪的信号采用双路光电检测法,经过高通滤波器、平方器,将两路信号相加后,实现了干涉仪信号无偏振衰落输出.其实验结果与理论分析一致. 相似文献
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J. C. West 《Waves in Random and Complex Media》2005,15(3):395-403
The phase interference fading in Bragg backscattering from the sea surface at moderate incidence angles is considered using both moment method calculation of the scattering from measured water profiles and an implementation of the slightly rough, tilted facet model. The fading of the instantaneous scattering cross-section is shown to be independent of the instantaneous phase of the illuminating signal. The vertical and horizontal polarization fading responses are therefore strongly correlated when identical carrier frequencies and modulations are used at both polarizations since the electromagnetic energy is Bragg resonant with the same small-scale roughness in both cases, independent of whether the polarization channels are phase locked. Instantaneous horizontally polarized Bragg backscattering (HH) exceeding that at vertical polarization (VV) is extremely unlikely in this case. Use of an offset in the frequencies of monochromatic signals used at the two polarizations can lead to reduced correlation between the fading if the illumination footprint length is sufficiently large so that the frequency shift introduces a significant additional phase shift between the scattering from the leading and trailing edges of the footprint. The fading shows only a very weak correlation when this phase shift exceeds 400°. HH Bragg backscattering exceeding VV will be much more common under these specialized conditions. 相似文献
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为了消除非线性因素对相位生成载波解调结果的干扰,降低相位生成载波解调过程中低通滤波器的频响特性对相位生成载波解调结果的影响,该文提出了一种基于扩展卡尔曼滤波椭圆参数估计的相位生成载波微分交叉相乘解调方法。该方法在综合考虑各种非线性因素对相位生成载波微分交叉相乘解调结果的影响的基础上,对传统的相位生成载波微分交叉相乘解调过程进行了改进。经过计算机仿真和实验验证,该文所提出的扩展卡尔曼滤波微分交叉相乘方法能够有效地抑制非线性因素对相位生成载波解调结果的干扰,相比传统的相位生成载波微分交叉相乘方法,其信噪比提高了35.0 d B,总谐波失真降低了30.7 dB,信噪谐波比提高了31.0 dB,且扩展卡尔曼滤波微分交叉相乘方法受解调过程中低通滤波器频响特性的影响较小。 相似文献
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We derive the expressions for the power fading including first-order polarization mode dispersion (PMD), chromatic dispersion,
chirp parameter as well as polarization-dependent chromatic dispersion (PCD), which is dependent on the angle of precession
of output state of polarization around the PMD vector. From the expression for radio frequency (RF) signals power fading,
we get the average power fading for chromatic dispersion, chirp parameter, first-order PMD and PCD for both double sideband
(DSB) modulation and single sideband (SSB) modulation. We also demonstrate a fast PMD and chromatic dispersion monitoring
technology with reduced polarization-dependent gain. The measured results agree well with theoretical analysis.
PACS 42.81.-i; 42.81.Gs; 42.30.Lr 相似文献
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We propose and demonstrate label encoding-swapping and transmission for an orthogonally labeled packet by use of a 10-Gbit/s amplitude shift keying payload and a 2.5-Gbit/s polarization shift keying (PolSK) label. A simple scheme for demodulating and demultiplexing the PolSK label based on an injection-locked Fabry-Perot laser diode is described. The extinction ratio of the newly added PolSK label can be precisely controlled and maintained after the intermediate node. 相似文献
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简单介绍了以经典Mie理论为基础的光散射测量技术在颗粒直径和颗粒浓度测量中广泛的应用。分别以Mie理论和离散偶极子近似理论(DDA)为基础, 用数值计算方法分析了球型颗粒的光散射特性,给出了微小颗粒对平行入射光散射的强度函数和散射偏振度的数值计算方法。得到了强度函数和偏振度随相关物理参量变化的三维图,为微小颗粒散射研究提供了一种三维视图。计算结果表明:当尺度参量x<4时,2种方法所得结果差异不大;随尺度参量增大,2种方法所得结果出现较大差异。与经典Mie理论相比,由于离散偶极子近似理论可以解决各种形状的颗粒散射问题,其应用前景更广泛。 相似文献