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11.
双芯复合格点光子晶体光纤的负色散特性 总被引:5,自引:1,他引:4
介绍了一种双芯复合格点负色散光子晶体光纤,其包层是由连续电介质纯硅背景上挖出的两种大小不同的空气孔构成,芯区是由掺锗的高折射率的材料构成。为了实现负色散,还移去了包层中的一圈空气孔。采用频域有限差分法对其负色散特性进行分析表明,通过调整空气孔间距和两种空气孔的尺寸,可以得到不同程度的宽带负色散。当内芯半径取0.95μm,孔间距取2.15μm,大空气孔直径取1.9μm,小空气孔直径取1.1μm时,可在1.55μm处实现宽带负色散,其半峰全宽超过了200 nm。这种光纤的包层中空气孔呈六边形分布,空气孔的尺寸均大于1μm,降低了制作的难度。这种光纤可以用于波分复用光纤通信系统中的宽带色散补偿。 相似文献
12.
In this paper, two kinds of modified surface plasmonic
waveguides formed by nanometric parallel lines are proposed. The
finite-difference frequency-domain method is used to study
propagation properties of the fundamental mode supported by these
surface plasmonic waveguide structures. Results show that the
transverse magnetic field of the fundamental mode is mainly
distributed in the face to face region formed by two rods. With the
same geometrical parameters and the same working wavelength of
632.8~nm, in the case of rods with a triangular cross-section, the
degree of localization of field is strong, i.e. the mode area is
small, but the fraction of the modal power in the metal increases,
so the effective index increases and the propagation length of the
mode decreases. With the same geometrical parameters, relative to
the case of a working wavelength of 632.8~nm, when working wavelength
is large, the mode area of transverse magnetic field distribution is
large, i.e. the degree of localization of field is weak, and the
interaction of field and silver is weak too, then the effective
index decreases, so the propagation length increases. The rounded
radii of rods have a great influence on the performance of the surface
plasmonic waveguides with rounded triangular cross-sections, but have
little influence on the performance of surface plasmonic waveguides
with rounded square cross-sections. Since the distribution of
transverse magnetic field, effective index, propagation length and
the mode area can be adjusted by the geometrical parameters, this
kind of modified surface plasmonic waveguide can be applied to the
field of photonic device integration and sensors. 相似文献
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We introduce a modified surface plasmonic waveguide with an arc
slot. The dependences of distribution of energy flux density,
effective index, propagation length and mode area of the symmetric
mode supported by this waveguide on geometrical parameters and
working wavelength are analysed by using the finite-difference
frequency-domain (FDFD) method. Results show that the energy flux
density distributes mainly in four corners which are formed by two
arcs, and the closer to the corners it is, the stronger the energy
flux density will be. The effective index, the propagation length
and the mode area are influenced by geometrical parameters,
including the width, the thickness and the arc radius of the surface
plasmonic waveguide, as well as the working wavelength. It has been
shown that the surface plasmonic waveguide with an arc slot has
better propagation properties than the surface plasmonic waveguide
with a straight slot. This work may be helpful for applying the slot
surface plasmonic waveguide to integrated photonics. 相似文献
15.
针对无线传感器网络中传感器节点随机分布造成能耗不均和“热区”等问题,提出了一种改进的基于蚁群算法的非均匀分簇路由协议。该协议也采用“轮”方式运行,每轮簇首选举开始阶段,根据节点剩余能量、节点密度,结合节点到Sink节点的距离来构造不均匀的竞选半径,每个节点根据竞选半径范围内邻居节点计算剩余能量比及距离偏差平均值,从而计算出其簇首竞争等待时间,采用时间等候簇首竞选机制来选举出簇首,平衡簇内的通信能耗;数据传输阶段,考虑剩余能量、通信能耗、链路质量、传输时延等因素,采用改进的蚁群算法构造最优传输路径,数据传输的同时更新信息素,从而达到自适应、动态优化地建立和维护传输路径。仿真结果表明,该路由协议能有效节约能量和均衡能耗,延长网络生命周期,改善链路质量,减少传输时延。 相似文献
16.
本文应用传输线理论对PBG结构带通滤波器进行分析,并在此基础上仿真、设计一种新颖的K波段的双模带通滤波器.光子带隙结构具有独特的带阻特性,对高次模具有很好的抑制特性,能够提高微波电路系统的抗干扰能力.由于PBG的慢波特性,使得带通滤波器的结构尺寸大为减小,符合系统小型化的要求.在此基础上,就这种结构应用Ensemble软件进行优化仿真.最后制作出滤波器并进行了测试.仿真结果与实验结果吻合很好,插入损耗为-4.5dB,通带中心频率为25.2GHz,-3dB带宽为1.8GHz,相对带宽7%. 相似文献
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改进的八重准光子晶体光纤的色散特性研究 总被引:1,自引:0,他引:1
设计了一种改进的准光子晶体光纤,其包层由呈准八重周期分布的空气孔构成,其中靠近芯区的两层小宅气孔的直径一致,第三层以外的大空气孔直径一致.采用带有良匹配层(APML)吸收边界的全矢量频域有限差分(FDFD)方法法其色散特性进行了数值分析,计算了孔间距取1.40~2.50 μm,小空气孔直径取0.10~0.50μm,大卒气孔直径取0.20~1.00μm的条件下这种光纤基模的色散曲线.结果表明,通过调节包层中两种不同尺寸的空气孑L的大小以及孔间距这三个参数,可以得到不同水平的平坦色散曲线. 相似文献
20.
本文给出介质加载双环背脊波导移相器的传输常数方程,计算了典型参数的相移,和损耗的频率特性。不但给出了最佳的差相移的频率特性,还指出了该器件的优值比普通矩形波导的高,另外,背脊的存在提供了良好的热传导,因此它具更高的平均功率容量。 相似文献