共查询到19条相似文献,搜索用时 125 毫秒
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本文提出一种新型函数光子晶体, 其折射率是空间位置函数. 由费马原理, 我们给出光在一维、 二维和三维函数光子晶体中的运动方程, 以及一维函数光子晶体的色散关系、 带隙结构和透射率, 再利用传输矩阵理论研究函数光子晶体周期数、 入射角和介质层的厚度等对透射率和禁带结构的影响, 计算发现通过选择不同的折射率空间分布函数, 可以得到比传统光子晶体更宽或更窄的禁带结构. 这样为我们设计不同带隙结构的光子晶体提供理论依据. 相似文献
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基于平面波展开法,以介电常数分别为1F/m和12F/m的物质构成三角晶格二维光子晶体,改变空气孔半径r与晶格常数a之间的大小,数值模拟得到了三角晶格二维光子晶体横磁模带隙,当r=.4α时形成三处三角晶格二维光子晶体横磁模的带隙,其中最大三角晶格二维光子晶体横磁模带隙出现在0.6766—0.8000Hz,差值为0.1234Hz。研究结论为光子晶体器件的制作提供参考。 相似文献
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《广西物理》2017,(3)
用有限时域差分方法(FDTD)对比研究了下列二维光子晶体的带隙:第1组,半径r=0.2μm圆柱,折射率n=4,晶格常数a=0.4μm;第2组,半径为r=0.2μm圆柱,折射率n=4,晶格常数a=0.6μm;第3组,内半径r_1=0.1μm,外半径r_2=0.2μm,折射率n=4,晶格常数a=0.4μm;第4组,内半径r_1=0.1μm,外半径r_2=0.2μm,折射率n=4,晶格常数a=0.6μm,并且对每一组光子晶体进行挖孔操作,然后比较不同填充率对光子晶体材料的带隙的影响,以及同种材料和结构、挖孔对带隙的影响。对于紧密排列的二维光子晶体,挖孔会使带隙向长波方向移动;对于填充率小的光子晶体,或者环形柱二维光子晶体,中间挖孔不影响带隙的范围。 相似文献
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异质镜像光子晶体的光子带隙研究 总被引:1,自引:0,他引:1
对异质镜像结构光子晶体(ABCCBA)N进行了研究。首先,利用一维介电体系中处理光传播的方法--传输矩阵法,详细推导了异质镜像光子晶体透射率的计算公式;然后,采用Matlab软件编程仿真并分析了光子带隙形成与镜像周期数目、光子带隙数目与光子晶体薄层厚度、光子带隙位置与入射角大小等的关系。结果表明:光子带隙的形成及变化主要受光子晶体薄层厚度及入射角大小变化的影响。通过改变影响光子晶体光子带隙的参数,可得到不同频段的光子带隙,用来制作高质量反射镜、滤波器和发光二极管等。 相似文献
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For two-dimensional photonic crystals involving infinitely long dielectric rods or air-holes on square or triangular lattices, a number of high performance 60° and 90° waveguide bends are obtained by solving optimization problems involving the radii of a few rods or air-holes as the degrees of freedom. In particular, the proposed 60° bends significantly outperform previous designs that insert three or five identical air-holes in the bend. The optimization problems are solved using a recently developed method based on the so-called Dirichlet-to-Neumann (DtN) maps of the unit cells. 相似文献
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In this paper we have studied solid-core square-lattice PCFs with circular and square shaped air-holes. We have estimated the V-parameter by using the step-index fiber approximation (SIFA) and calculated numerical apertures for the structures considered. In order to estimate the effective core radius of the structure with the square shaped air-holes we have used an approximation based on the air-filling fraction. 相似文献
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The slow light and group velocity dispersion properties of 2D triangular lattice photonic crystal line defect waveguide (PCW) with square and circular air-holes are numerically investigated with the plane-wave expansion method. The simulation results show that the guided mode is impacted slightly by the cross section’s shape of the air-holes of the same filling ratio. Adjusting two rows of the inner-hole adjacent to the waveguide and modifying the waveguide width can bring in low-group velocity and low-dispersion (LVLD) region, in which the group index of the square holes can reach 210 which is far better than the circular-holes. At the same air-hole size and waveguide width, the PCW with the square holes can support higher bit rate of the signal up to 35 Gb/s. These results provide important theoretical basis for realizing of optical buffering and optical logic devices in all-optical network. 相似文献
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Propagation in perturbed one-dimensional phononic or photonic crystals, with bothcompositional and positional disorder, is considered. The coherent potential approximationis used to obtain the band structure and the Floquet normal form of theperiodic-on-average perturbed crystal, which is modified differently with respect to thetwo kinds of disorder. For finite size crystals, the transmission amplitude is calculatedand compared to direct numerical simulations and to an estimate based on localizationlength. The transmission spectrum is found to be better described using the fullexpression of the Floquet modes of the disordered, but periodic on average, medium. 相似文献
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A novel refractometric sensor utilizing unique spectral properties of antiresonant-guiding microstructured optical fibers is proposed. The sensor operation is based on the wavelength shift of the transmission spectrum in response to the refractive index change of a sample loaded in the air-holes of the microstructured optical fiber. Refractive index changes on the order of 0.1% can be detected using less than a nanoliter of a sample. 相似文献
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The disorder effect on the performance of novel waveguides constructed in two-dimensional amorphous photonic materials 下载免费PDF全文
On the basis of two-dimensional amorphous photonic materials,we have designed a novel waveguide by inserting thinner cylindrical inclusions in the centre of basic hexagonal units of the amorphous structure along a given path.This waveguide in amorphous structure is similar to the coupled resonator optical waveguides in periodic photonic crystals.The transmission of this waveguide for S-polarized waves is investigated by a multiple-scattering method.Compared with the conventional waveguide by removing a line of cells from amorphous photonic materials,the guiding properties of this waveguide,including the transmissivity and bandwidth,are improved significantly.Then we study the effect of various types of positional disorder on the functionality of this device.Our results show that the waveguide performance is quite sensitive to the disorder located on the boundary layer of the waveguide,but robust against the disorder in the other area in amorphous structure except the waveguide border.This disorder effect in amorphous photonic materials is similar to the case in periodic photonic crystals. 相似文献
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Analysis of propagation characteristics for an octagonal photonic crystal fiber (O-PCF) 总被引:1,自引:0,他引:1
Jung-Sheng Chiang 《Optics Communications》2006,258(2):170-176
An octagonal photonic crystal fiber (O-PCF) structure with eight air-holes on the first ring is proposed based on a unit isosceles triangle. The propagation characteristics and cut-off behaviors of the O-PCF and the standard hexagonal PCF (H-PCF) are numerically investigated by combining the vector boundary method and the effective area method. The phase boundaries for cut-off, single-mode, and multi-mode operations between the O-PCF and H-PCF are calculated and compared. It is found that under the same pitch Λ and air filling fraction (AFF) of the air-holes the O-PCF has significantly wider wavelength range operating in single-mode region, more circular-like field distribution, and less confinement loss than the H-PCF. 相似文献
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Dispersion and polarization properties of elliptical air-hole-containing photonic crystal fibers 总被引:3,自引:0,他引:3
Jingyuan Wang Chun Jiang Weisheng Hu Mingyi Gao Hongliang Ren 《Optics & Laser Technology》2007,39(5):913-917
In this paper, we investigate the dispersion and polarization properties of photonic crystal fiber with one ring or more rings of elliptical air-holes using plane-wave expansion (PWE) method. By introducing three rings of elliptical air-holes, PCF with ultra-low and ultra-flattened dispersion is designed and a total dispersion curve between ±0.5 ps/nm/km from 1315 to 1855 nm wavelength range is demonstrated. Furthermore, the polarization property of these elliptical air-hole-containing PCFs is analyzed and the variation of the birefringence with the area and ellipticity of the elliptical air-holes are discussed. 相似文献
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New nonlinear and dispersion flattened photonic crystal fiber with low confinement loss 总被引:1,自引:0,他引:1
A new nonlinear dispersion flattened photonic crystal fiber with low confinement loss is proposed. This fiber has threefold symmetry core. The doped region in the core and the big air-holes in the 1st ring can make high nonlinearity in the PCF. And the small air-holes in the 1st ring and the radial increasing diameters air-holes rings in cladding can be used to achieve the dispersion properties of the PCF. We can achieve the optimized optical properties by carefully selecting the PCFs structure parameters. A PCF with flattened dispersion is obtained. The dispersion is less than 0.8 ps/(nm km) and is larger than −0.7 ps/(nm km) from 1.515 μm to 1.622 μm. The nonlinear coefficient is about 12.6456 W−1 km−1, the fundamental mode area is about 10.2579 μm2. The confinement loss is 0.30641 dB/km. This work may be useful for effective design and fabrication of dispersion flattened photonic crystal fibers with high nonlinearities. 相似文献