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应用全矢量有限元方法,研究大间距Kagome结构空芯光子晶体光纤中纤芯的大小、形状与壁厚对光纤传输损耗谱的影响。结果表明,某些纤芯尺寸会造成包层中的结构缺陷,易使纤芯基模、表面模及包层模之间发生能量耦合,产生较大损耗。而纤芯形状与壁厚的改变会引起表面模式的变化,从而影响发生在基模与表面模之间反向耦合的位置和强度,使光纤传输频带变窄和损耗变大。据此,提出Kagome结构光纤的纤芯设计思路,即纤芯的大小应使包层保持完整的微结构,纤芯形状应与包层中的单元微结构相楔合,纤芯壁厚应与包层中玻璃支柱的宽度相同。 相似文献
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为了深入理解双包层光纤的光场传输特性,应用耦合模理论将双包层光纤等效为相互耦合的单模光纤和环形芯光纤,研究了圆对称的双包层光纤的光场传输.通过计算单模光纤LP01模和环形芯光纤导模的耦合系数发现了环形芯光纤LP0n模的耦合系数远大于其它导模的耦合系数,且LP0n模中的高阶模比低阶模的耦合系数大.据此,应用耦合模理论计算得到了该双包层光纤的光传输特性,计算结果发现光场沿光纤轴向呈近似周期分布,且纤芯中光功率变化的平均周期随波长递增,但平均归一化功率与光纤参数紧的选择有关. 相似文献
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为了深入理解双包层光纤的光场传输特性,应用耦合模理论将双包层光纤等效为相互耦合的单模光纤和环形芯光纤,研究了圆对称的双包层光纤的光场传输.通过计算单模光纤LP01模和环形芯光纤导模的耦合系数发现了环形芯光纤LP0n模的耦合系数远大于其它导模的耦合系数,且LP0n模中的高阶模比低阶模的耦合系数大.据此,应用耦合模理论计算得到了该双包层光纤的光传输特性,计算结果发现光场沿光纤轴向呈近似周期分布,且纤芯中光功率变化的平均周期随波长递增,但平均归一化功率与光纤参数紧的选择有关. 相似文献
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利用两种方法研究了高速光脉冲在具有交叉相位调制的等边三角形排列结构的非线性三芯光纤耦合器中传输和开关特性.首先利用变分原理得到三纤芯中传输转移系数随距离变化的方程,然后利用分裂步长傅里叶方法求得了光脉冲的数值解.变分法和数值模拟的结果表明:当一阶模间色散系数较小时,光脉冲仍能在三芯之间周期性耦合传输,并且表现出良好的开关特性,但是随着一阶模间色散系数的增大,脉冲耦合传输的周期性和陡峭的开关特性都遭到破坏,光脉冲在传输中发生分裂;二阶耦合色散系数和初始啁啾都能使光脉冲传输时的耦合长度变短、光脉冲在三纤芯之间
关键词:
三芯光纤耦合器
模间色散系数
耦合长度
开关阈值功率 相似文献
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饱和长度对少模光纤光栅影响的数值仿真 总被引:1,自引:0,他引:1
对折射率剖面非均匀的少模光纤Bragg光栅(FM-FBG)的反射特性进行了数值仿真,研究了光纤侧面紫外曝光法制作的光纤光栅中饱和长度的影响.用试射法(shooting)数值求解了耦合模方程,得到FM-FBG的反射谱.仿真结果表明,在纤芯和包层边界的最大光致折射率变化量和纤芯吸收因子不变的情况下,随着纤芯折射率变化的饱和长度的增大,LP01和LP11模间的互耦合反射峰呈抛物线形变化,当饱和长度增大到一定值后,互耦合反射峰随饱和长度的增大而逐渐减小并最终消失;同阶LP模的自耦合反射峰随饱和长度的增大而增大. 相似文献
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We present a coupled-mode theory of fiber-optic add-drop filters, which involve directional coupling between two fibers combined with fiber Bragg gratings defined inside the coupling region. The analysis self-consistently accounts for both the directional and the reflection coupling, and the propagation constants and structure of the supermodes of the combined structure are derived. We present a detailed analysis of a filter design based on identical fibers. The calculated device parameters satisfy the requirements for dense wavelength-division multiplexing applications. 相似文献
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在考虑到各向同性光纤和各向异性光纤在横向应力作用下介电常量变化量差别的条件下,利用弹光效应和折射率椭球得到了外界横向应力与保偏光纤介电常量变化量的关系.采用耦合模理论分析了横向应力作用下保偏光纤偏振耦合特性,数值模拟了横向应力大小、方向以及作用长度对偏振耦合强度的影响,应力作用方向与主轴(未受外力)成45°时,光纤受扰最敏感|输出消光比随力作用长度呈现周期性变化,力的作用大小不同,交换能量周期也不同|在应力大小部分区域输出消光比和横向应力大小成线性关系,结论与已有实验结果一致. 相似文献
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Coupling properties of two gain-guided, index-antiguided (GG + IAG) fibers, or GG + IAG fibers and index-guided (IG) fibers, were investigated by the further general coupled-mode theory. The theory can explain any situation of two fiber coupling. The interesting results were obtained by the numerical computation method. For two GG + IAG fiber coupling, total power was decreased as rising real-valued refractive-index difference (real part of refractive-index difference between core and cladding, RVRID), while the power of one GG + IAG fiber was damped oscillations with increased core separation. In the GG + IAG fiber and IG fiber coupler, the variation of the RVRID could change coupling characteristics. These results are different from two IG fibers coupling, and the general coupled-mode theory may provide meaningful references for new concepts of directional coupler and pumping technology of GG + IAG fiber. 相似文献
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1 Introduction Grating assisteddirectionalcouplerisanattractiveadd dropfilterfordensewavelength divisionmultiplexing (DWDM ) .Anumberofsuchadd dropfiltershavebeenproposedanddemonstrated[1~ 5] .Twomainapproacheshavebeen proposedtosimulate gratingeffectindirect… 相似文献
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A new coupled-mode formulation is developed for grating-assisted parallel optical fiber cores. The theory is derived from the scalar wave equation by perturbation method. The diffraction caused by grating and coupler in the grating region are both considered. Based on the theory, various experimental phenomena in grating-assisted parallel optical fiber cores can be simulated accurately. 相似文献
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不在同一平面的空间多波导中光耦合发生在横截面两个方向,利用空间多波导可以方便、有效地实现不同层间器件的互连。将平面波导耦合模理论推广到空间多波导之间的耦合,在弱导引条件下给出了空间多波导的耦合方程。利用该耦合方程对三维集成光学器件中常见的空间三波导和空间四波导的耦合特性进行分析,得出光强分布及耦合长度的解析表达式,并用三维全矢量光束传输法验证了分析结果。分析结果表明利用空间多波导可以实现水平和垂直两个方向上的均匀或非均匀分束,为利用空间多波导之间相互耦合的三维定向耦合器件的设计和分析提供理论基础。 相似文献
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A novel class of microstructured optical fiber coupler is introduced that operates by resonant, rather than proximity, energy transfer by means of transverse light guides built into a fiber cross section. Such a design permits significant spatial separation between interacting fibers, which, in turn, eliminates intercore cross talk owing to proximity coupling. A controllable energy transfer between the cores is then achieved by localized and highly directional transmission through a transverse light guide. The main advantage of this coupling scheme is its inherent scalability, as one can integrate additional fiber cores into the existing fiber cross section simply by placing the cores far enough from the existing optical circuitry to prevent proximity cross talk and then making the necessary intercore connections with transverse light wires, in direct analogy with on-chip electronics integration. 相似文献
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In this paper, coupled-mode theory is applied to a two-core microstructured optical fiber for the first time to calculate the coupling coefficients for different fiber structures by employing a simple effective index model approach. The dependence of the mode coupling properties upon the geometrical parameters of the two-core structures (air-hole arrangement, hole size, and pitch size) and wavelength are evaluated systematically. The effective index coupled-mode theory is compared with the finite-element method based super-mode theory in details and the results show good agreement. The coupling characteristics are proven to be insensitive to the longitudinal strain by considering the photoelastic effects. 相似文献
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Using conventional coupled-mode theory, a set of coupled-mode equations are formulated for single-helix chiral fiber long-period gratings. A helical-core fiber is analyzed as an example. The analysis is simple in mathematical form and intuitive in physical concept. Based on the analysis, the polarization independence of mode coupling in special fiber gratings is revealed. The transmission characteristics of helical-core fibers are also simulated and discussed. 相似文献