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1.
In this paper, a highly birefringent index-guiding photonic crystal fiber with low confinement loss is proposed by enlarging the central row of air holes in the structure. By employing the multipole method, properties of this structure, including the effective index, birefringence and confinement loss, are investigated. Simulation results indicate that high birefringence of 1.65 × 10−3 can be reached at the wavelength of 1.55 μm, and a low confinement loss on the order of 10−6 dB/km can be achieved at the same wavelength. Moreover, the impacts of air hole sizes on birefringence and confinement loss are also analyzed in detail. 相似文献
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The present paper proposes a novel design for achieving single-polarization single-mode (SPSM) operation at 1550 nm in photonic crystal fiber (PCF), using a rectangular-lattice PCF with two lines of three central air holes enlarged. The proposed PCF composed entirely of silica material is modeled by a full-vector finite element method with anisotropic perfectly matched layers. Simulations show that single-polarization operation within broad wavelength range can be easily realized with the proposed structure. The wideband SPSM operation features, the low confinement losses, and the small effective mode area are the main advantages of the proposed PCF structure. A SPSM-PCF with confinement loss less than 0.1 dB/km within wavelength range from 1370 to 1610 nm and effective mode area about 4.7 μm2 at 1550 nm is numerically demonstrated. 相似文献
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Theoretical analyses on improved beam properties of GaSb-based 2.X-μm quantum-well diode lasers with no degradation in laser parameters
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An asymmetric laser heterostructure is developed to improve the beam properties of GaSb-based diode lasers with no degradation in laser parameters.Employing the semivectorial finite difference method,the dependences of beam divergence and optical confinement factor on waveguide width and refractive index step are investigated theoretically.After carefully design,a particular asymmetric laser structure is proposed.Its beam divergence in the fast axis is reduced from 61° to 34° compared with that of the broad-waveguide structure.The optical confinement factor is approximately equal to 0.0362 and comparable to that of the conventional broad-waveguide structure. 相似文献
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何忠蛟 《中国光学快报(英文版)》2009,7(5):387-389
Highly birefringent elliptical-hole photonic crystal fibers (PCFs) with single defect and double defects are proposed, which are supposed to be achieved by extruding normal circular-hole PCFs based on a triangular-lattice photonic crystal structure. Comparative research on the birefringence and the confinement loss of the proposed PCFs with single defect and double defects is presented. Simulation results show that the proposed PCFs with single defect and double defects can be with high birefringence (even up to the order of 10^-2). The confinement loss increases when the ellipticity of the air hole of the PCFs increases, which nevertheless can be overcome bv increasing the ring number or the air holes in the fiber cladding. 相似文献
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Jing Xiao Jiansheng Liu Zheng Zheng Yusheng Bian Guanjun Wang Shuna Li 《Optics Communications》2012,285(17):3604-3607
In this paper, a novel metal-insulator-semiconductor waveguide with an air core in the insulator layer is proposed in order to improve the on-chip integration. Compared with the structure with homogeneous insulator, the introduced air core provides an additional degree of freedom for tuning the characteristics of the hybrid plasmonic mode. Simulation results demonstrate that the proposed structure exhibits better tradeoff between the mode confinement and the propagation length. The relatively low crosstalk between adjacent proposed waveguides could be achieved and the coupling efficiency between conventional silicon waveguide and the proposed structure maintain. The proposed waveguide could be used to build ultra-compact photonic components and enable on-chip integration of photonic circuits. 相似文献
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A novel hole-assistant microstructured optical fiber with a rectangle-like core and four elliptical holes as cladding is proposed. By employing a full-vector finite element method, the modal birefringence and confinement loss are numerically investigated, and the results show that in such a structure, an ultrahigh modal birefringence of 2.91×10−2 and a low confinement loss (<1 dB/km) can be simultaneously obtained at excited wavelength of 1.55 μm. It is significant that such a microstructured optical fiber is easily fabricated with its simple structure and exhibits improved performance. 相似文献
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A scheme of combining the theory of many instantons and the effective Lagrangian of QCD is proposed to study the nucleon structure. With this approach, the vacuum structure of nonperturbative QCD is discussed and a reasonable potential of quark confinement is obtained. The calculated results of the constituent quark mass and the decay constant of pion agree with experimental data quite well. 相似文献
9.
A six-quark state with the benzene-like color structure based on a color string model is proposed and studied. Calculation with quadratic confinement with multi-string junctions shows that such a state has a ground state energy similar to that of other hidden color six-quark states proposed so far. Its possible effect on NN scattering is discussed. 相似文献
10.
A new type of THz waveguides, which employs a solid polyethylene rod as the core and polyethylene tubes in a periodic array of square lattice as the cladding, is proposed. Optical properties of this new THz waveguide, especially in dispersion, confinement loss and single mode property, are investigated in detail with the plane wave expansion method and the beam propagation method. Numerical results demonstrate that the new THz waveguide can reach not only low dispersion but also low confinement loss at single mode propagation. Therefore, the square lattice structure is a better candidate as THz waveguides than the triangular ones. 相似文献
11.
Shubi F. Kaijage Yoshinori Namihira Nguyen H. Hai Feroza Begum S. M. Abdur Razzak Tatsuya Kinjo Hiroki Higa Nianyu Zou 《Optical Review》2008,15(1):31-37
In this paper, we present a dispersion controlling technique with a multiple defect-core hexagonal photonic crystal fiber
(MD-HPCF). By omitting air holes in the core region of the conventional HPCF and adjusting the size of air holes around the
newly formed core, we can successfully design low flattened dispersion PCF with low confinement loss, as well as high birefringence.
The low flattened dispersion feature, as well as the low confinement losses and high birefringence are the main advantages
of the proposed PCF structure, making it suitable as chromatic dispersion controller, dispersion compensator, and/or polarization
maintaining fiber. 相似文献
12.
Sheng Jiang Andrew G. Krygier Douglass W. Schumacher Kramer U. Akli Richard R. Freeman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(10):1-8
A new type of a coaxial multi-layer plasmonic waveguide is proposed. The mode propagation properties are analyzed at the communication working wavelength. Theoretical investigations reveal that the enhanced optical confinement can be achieved in the two low-index dielectric media layers. The mode size can be sub- or deep sub-wavelength scale. The mode propagation loss can be well compensated by replacing the high-index dielectric media with gain material to achieve longer propagation length with better mode confinement. The comparisons of the mode properties between the proposed waveguide and waveguides studied in the published literatures are also considered. These investigations potentially lay the groundwork for the further applications of nanowire type multilayer hybrid structures. This structure could also enable various applications such asnanophotonic waveguides, high-quality nanolasers, and optical trapping and biosensors. 相似文献
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Tunable coupling of a hybrid plasmonic waveguide consisting of two identical dielectric cylinders and a silver film
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The propagation length of surface plasmon polaritons(SPPs) is intrinsically limited by the metallic ohmic loss that is enhanced by the strongly confined electromagnetic field. In this paper, we propose a new class of hybrid plasmonic waveguides(HPWs) that can support long-range SPP propagation while keeping subwavelength optical field confinement. It is shown that the coupling between the waveguides can be well tuned by simply varying the structural parameters. Compared with conventional HPWs, a larger propagation length as well as a better optical field confinement can be simultaneously realized. The proposed structure with better optical performance can be useful for future photonic device design and optical integration research. 相似文献
15.
A novel kind of large mode area photonic crystal fibers (PCFs) are proposed in this paper. In order to achieve large effective mode area, a novel technique is applied to seven missing air hole PCF structures. The modal characteristics of PCF structures such as effective mode area, confinement loss, chromatic dispersion properties with doped cores, are investigated by employing the full vectorial finite element method (FEM). Simulation results demonstrate that effective mode area and confinement losses of fundamental mode simultaneously improved by applying our novel technique to proposed structures. The effects of bending on confinement losses of the proposed PCFs have been thoroughly investigated. Additionally, confinement losses of first higher order modes are presented and the possibility of stripping them in a simple way is discussed. 相似文献
16.
Feroza Begum Yoshinori Namihira S. M. Abdur Razzak Shubi Kaijage Kazuya Miyagi Nguyen Hoang Hai Nianyu Zou 《Optical Review》2007,14(3):120-124
A new simple structure of an index-guiding highly nonlinear dispersion-flattened square photonic crystal fiber (HNDFSPCF)
with low confinement losses is proposed. The results reveal that it is possible to design five-rings HNDF-SPCFs with a flattened
dispersion of 0.43 ps/(nm·km), low dispersion slope of -0:02 ps/(nm2·km), low confinement loss of approximately 103 dB/m, and a large nonlinear coefficient of approximately 35W-1 km-1 at 1.55 μm. It is also observed that the confinement loss is less than 10-1 dB/m in the wavelength range of 1.2 –1.7 μm. 相似文献
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《中国物理 B》2019,(4)
We propose a novel structure for tunnel junction based on delta-doped AlGaAs/GaAs quantum wires. Higher spatial confinement of quantum wires alongside the increased effective doping concentration in the delta-doped regions extremely increase the peak tunneling current and enhance the performance of tunnel junction. The proposed structure can be used as tunnel junction in the multijunction solar cells under the highest possible thermodynamically limited solar concentration.The combination of the quantum wire with the delta-doped structure can be of benefit to the solar cells' advantages including higher number of sub-bands and high degeneracy. Simulation results show a voltage drop of 40 mV due to the proposed tunnel junction used in a multijunction solar cell which presents an extremely low resistance to the achieved peak tunneling current. 相似文献
20.
提出一种用于液体传感的光子晶体光纤的结构和设计方法。将六边形光子晶体光纤的纤芯区域设计成2个椭圆空气孔,分别填充水和乙醇,进而比较两种光子晶体光纤结构的传播特性。采用全矢量有限元法对所设计光子晶体光纤结构的双折射、相对灵敏度、限制损耗、非线性系数进行数值分析,对光纤各项参数的优化及纤芯椭圆结构参数进行调整,结果表明:当椭圆率为0.6时,纤芯填充乙醇的光子晶体光纤PCF2在波长1.55 nm处相对敏感度可达到72.506 7%,同时限制损耗可以降至10?8级。所设计的模型可用于传感和生物传感研究及应用。 相似文献