共查询到20条相似文献,搜索用时 250 毫秒
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针对通过增加光源谱宽度来提高光学相干层析成像系统分辨率时样品色散特性的限制作用,分析了色散与光学相干层析成像系统纵向光程分辨率的约束关系.根据物质色散特性,采用数值变换方法对光学相干层析成像相干成像信号进行了色散补偿.实验使用了中心波长1 550 nm 自激发辐射光源和光纤迈克尓逊干涉结构,对水和光学快速扫描延迟线引入的二阶和三阶色散进行了数值补偿并通过相位修正因子来改善补偿效果.确定了一种普适的、快速的数值色散补偿方法.在对水中盖玻片和生物组织和的光学相干层析成像图像的色散补偿实验中取得了良好的效果,证明了方法的可行性. 相似文献
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光学相干层析成像色散补偿研究 总被引:2,自引:2,他引:0
针对通过增加光源谱宽度来提高光学相干层析成像系统分辨率时样品色散特性的限制作用,分析了色散与光学相干层析成像系统纵向光程分辨率的约束关系.根据物质色散特性,采用数值变换方法对光学相干层析成像相干成像信号进行了色散补偿.实验使用了中心波长1550nm自激发辐射光源和光纤迈克尓逊干涉结构,对水和光学快速扫描延迟线引入的二阶和三阶色散进行了数值补偿并通过相位修正因子来改善补偿效果.确定了一种普适的、快速的数值色散补偿方法.在对水中盖玻片和生物组织和的光学相干层析成像图像的色散补偿实验中取得了良好的效果,证明了方法的可行性. 相似文献
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用于频域光学相干层析成像的深度分辨色散补偿方法 总被引:4,自引:2,他引:2
提出一种深度分辨的色散补偿方法,用于增强频域光学相干层析成像的纵向分辨率。将频域光学相干层析成像采集的干涉谱信号傅里叶变换到空域,获取对应不同深度的干涉谱条纹相位,通过对其进行调整实现对被测样品不同深度处的色散的精确补偿。避免传统方法中采用统一色散系数进行色散补偿所带来的过补偿与欠补偿误差,可以有效消除色散引起的频域光学相干层析成像系统点扩展函数的展宽和扭曲。模拟和实验结果表明,基于深度分辨的色散补偿方法在样品的全深度探测范围内可以达到较佳的补偿效果,可有效提高光学相干层析成像系统的纵向分辨率。 相似文献
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群速度色散会限制太赫兹量子级联激光器频率梳的稳定以及频谱宽度.对于太赫兹量子级联激光器频率梳,其色散主要由器件增益、波导损耗、材料损耗引起.研究基于4.2 THz量子级联激光器双面金属波导结构,通过建立德鲁德模型,利用有限元法计算了激光器的波导损耗;器件未钳制的增益由费米黄金定则计算得到,结合增益钳制效应,计算了器件子带电子跃迁吸收以及镜面损耗,得到了器件钳制后的增益;利用Kramers-Kronig关系得到了器件的增益、波导损耗、材料损耗引起的色散,结果表明器件的激射区域存在非常严重的色散(–8×10~5—8×10~5 fs~2/mm).同时,计算了一种基于Gires-Tournois干涉仪结构的色散,结果表明,该结构的色散具有周期性,可以用于太赫兹量子级联激光器的色散补偿. 相似文献
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液晶是目前显示器件的重要材料.向列型液晶在其光学性质上类似单轴晶体.液晶的随波长改变的双折射率是基本的物理常数之一.测量液晶的双折射率及其色散的方法,主要有折射法与干涉法.而在测量双折射率的色散方面,干涉法要比折射法简便得多.干涉法所测得的是光程,即noh,neh以及光 相似文献
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Chromatic dispersion (CD) caused by an imperfect antireflection coating is a great concern for optical engineers, and different techniques have been proposed to reduce CD in optical devices. In this article, we investigate two popular CD reduction techniques used in birefringent interleaver manufacturing and their effects on performance improvement of optical communication systems. Our results show that some CD reduction scheme bringing about a smaller CD ripple amplitude does not necessarily guarantee better system performance. This result can be used as a guideline for optical engineers working on reducing CD caused by an imperfect antireflection coating. 相似文献
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系统分析了三镜级联结构G-T谐振腔的色散特性,表明三镜级联结构G-T谐振腔具有不同于两镜级联结构G-T谐振腔的特有色散特性.利用该特性以三镜级联结构G-T谐振腔作为色散补偿元件可有效改善MGTI型interleaver的色散性能,并给出了以三镜级联结构G-T谐振腔为补偿元件的具体补偿实例.模拟结果表明:对50 GHz的MGTI型光交错复用器,可实现中心波长附近±0.08 nm、±0.09 nm和±0.1 nm范围内的色散绝对值分别小于1 ps/nm、2.4 ps/nm和6.6 ps/nm的良好的补偿结果.与文献报道的两镜级联结构G-T腔补偿结果相比,色散绝对值小于1 ps/nm的波长范围扩大了60%;在中心波长附近±0.09 nm范围内的色散绝对值降低了92%. 相似文献
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A novel C + L band polymeric PLC interleaver using Y-junction structure is reported. The principle of operation and the fabrication are described, and the alignment and temperature characteristics are also investigated. This interleaver has wide bandwidth of operation, about 50 nm. The channel spacing is 1.6 nm and maximum isolation 28 dB. 相似文献
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Spectrum distortion in a birefringent crystal-based interleaver filter introduced by the right-angle total internal reflection retroreflector is studied. The phase shift between two perpendicularly polarized components of the polarized light incident onto the retroreflector is calculated. The sensitivity of the phase shift to the incident angle for different materials from which the retroreflector is made is also considered. This study indicates that the phase shift is less sensitive to the incident angle for retroreflectors having a higher index of refraction, suggesting a fixed-phase compensator that can be used to cancel out the phase shift introduced by the retroreflector to recover the interleaver filter's spectrum. The fold-back 50 GHz channel spacing birefringent crystal interleaver filter is fabricated to demonstrate that the spectrum distortion due to the phase shift introduced by retroreflector can be eliminated by a phase compensator. 相似文献
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基于数字信号处理中的IIR理论,提出了一种基于MGTI型interleaver的新颖设计方法,可以简便地得到所求的各组结构参量.通过z变换简化透射方向和反射方向光波电矢量的表达式,分析了零极点位置对整个滤波器的影响,利用IIR中椭圆滤波器的设计方法得到Gires Tournois腔的腔长、臂长差和Gires Tournois腔各镜面的反射率.并给出了利用两个双镜Gires Tournois腔替代两面全反镜所得到的三组不同参量,比较了采用不同Gires Tournois腔所得到的相应的1、3、5、7、9阶interleaver的模拟仿真结果. 相似文献
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We report a high-quality interleaver with frequency spacing of 25 GHz, which is made by a Michelson interferometer with a mirror replaced by a Gires–Tournois etalon. Our optimal design and elaborate manufacture assure its excellent performance. We present the analysis of performance parameters, design of structural parameters, the unique fabrication technology and testing results of this interleaver in this paper. 相似文献
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We propose and demonstrate a flat-top 25-GHz birefringent interleaver using a novel ring-cavity architecture. The ring-cavity provides the phase shifts needed to achieve a flat-top spectral passband at the output. Fresnel reflectivities (for s- and p-polarization states) at the prism-air interface of the ring cavity are employed so that highly accurate thin-film coatings are not needed for the phase shifts. By choosing the appropriate incident angle near the Brewster angle, the optimum interface reflectivities for flat passbands and low crosstalk can be obtained. The ring cavity based interleaver in a 25-GHz channel spacing application exhibits a 0.5-dB passband larger than 0.14 nm, a 25-dB stopband greater than 0.14 nm, and a channel isolation higher than 28 dB over the entire C-band. 相似文献