共查询到20条相似文献,搜索用时 15 毫秒
1.
设计了一种新颖结构的双层芯色散补偿光子晶体光纤。此光纤在整个C波段具有高负色散特性。通过合理选取双层芯光纤的外层芯层数,同时优化孔间距和空气孔直径,设计的光纤在C波段的色散值在-520ps/(km.nm)和-390ps/(km.nm)之间近似线性变化,残余有效色散系数近似为零,相关色散斜率(RDS)在0.0032nm-1的色散补偿光纤,其RDS值与标准单模光纤匹配,有效模场面积优于常规色散补偿光纤,可以对其长度30倍以上、用于宽带传输的标准单模光纤进行良好的色散和色散斜率补偿。 相似文献
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This paper investigates a novel type of optical fiber which is composed of three portions: the core, inner cladding, and outer cladding. It is assumed that the core has the largest refractive index of the three, and the outer cladding index is the next largest. When the index difference between the core and the inner cladding is much larger than that between the outer cladding and the inner, the new fiber has a stronger confinement property than a usual singly clad fiber in the single-mode region. It is also assumed that the inner-cladding thickness is larger than or comparable with the core radius. This confinement is the origin of the following three properties of potential importance in single-mode optical communication. 1) As compared with a singly clad fiber, the largest core area for single-mode operation is roughly twice. 2) The group delay arising from waveguide characteristics has an opposite sign against that of typical glass dispersion. (Singly clad fiber has a dispersion of the same sign.) 3) The field is much more tightly confined within the core as compared with a singly clad fiber. This minimizes extra attenuation due to absorption in the cladding. 相似文献
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双包层单模光纤光学参数对传输特性的影响 总被引:1,自引:0,他引:1
对特征方程直接求导解得了基模群时延和群速色散,讨论了双包层单模光纤不同折射率分布对传播常数、群时延、群速色散以及零色散点波长的影响.研究结果表明:光学参数,即纤芯和外包层的相对折射率(P)以及内包层和外包层的相对折射率(R)对该类光纤的传播常数、群速度、群速色散和零色散点波长均有比较明显的影响,影响的大小及规律随参数的不同又有所不同.这些规律为设计满足不同色散要求的双包层单模光纤提供了理论依据. 相似文献
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The waveguide and material dispersion are investigated for various silica-based single-mode optical fibres with arbitrary refractive-index profiles. It is shown that in the case of the doubly clad optical fibre with an index difference between the core and the outer cladding ?1=1% and that between the inner cladding and the outer ?2=?1%, the diameter of the core 2a=7.2 ?m, and the thickness of the inner cladding t=0.3a, the total dispersion is reduced within ± 1 ps/km/nm over a wide spectral range of ?=1.35?1.67 ?m. 相似文献
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Shuqin LOU Shujie LOU Tieying GUO Liwen WANG Weiguo CHEN Honglei LI Shuisheng JIAN 《中国光电子学前沿》2009,2(2)
Our recent research on designing microstruc-tured fiber with novel dispersion properties is reported in this paper. Two kinds ofphotonic crystal fibers (PCFs) are introduced first. One is the highly nonlinear PCF with broadband nearly zero flatten dispersion. With introducing the germanium-doped (Ge-doped) core into highly non-linear PCF and optimizing the diameters of the first two inner rings of air holes, a new structure of highly non-linear PCF was designed with the nonlinear coefficient up to 47 W-1·km-1 at the wavelength 1.55 μm and nearly zero flattened dispersion of ±0.5 ps/(km·nm) in telecom-munication window (1460-1625nm). Another is the highly negative PCF with a ring of fluorin-doped (F-doped) rods to form its outer ring core while pure silica rods to form its inner core. The peak dispersion - 1064 ps/(km·nm) in 8 nm full width at half maximum (FWHM) wavelength range and -365ps/(km·nm) in 20nm (FWHM) wavelength range can be reached by adjusting the structure parameters. Then, our recent research on the fabrication of PCFs is reported. Effects of draw parameters such as drawing temperature, feed speed, and furnace temperature on the geometry of the final photonic crystal fiber are investigated. 相似文献
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太赫兹纤维波导是太赫兹系统中重要的组成元件。为了实现太赫兹辐射的低损耗低色散传输,设计了一种以环烯烃共聚物为基质的多孔太赫兹纤维,并利用基于全矢量有限元法的商业软件COMSOL 分析了该多孔太赫兹纤维的传输特性,着重考察了亚波长多孔纤芯的结构参数对传输特性的影响。结果表明,这种太赫兹纤维可以将模场能量很好地限制在亚波长多孔纤芯中传输,具有较小的有效模场面积、低的传输损耗和平坦近零色散等优良的传输特性;同时,通过增大多孔纤芯的占空比,可以将更多的模场能量限制在亚波长直径的空气孔洞中传输,并减小太赫兹纤维的有效模场面积和有效模式损耗,但同时会增大限制损耗和色散。 相似文献
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Transmission characteristics of a coaxial optical fiber line 总被引:1,自引:0,他引:1
A coaxial optical fiber line is proposed and studied as a long-distance transmission medium. The radial structure consists of a core surrounded by two clads. The inner clad has higher refractive index than the core and the outer clad. Guided modes are thus characterized by a concentrated field in the inner clad and evanescent fields in both the core and the outer clad. Using a rigorous modal analysis, characteristic curves for a monomode coaxial fiber line are presented. It is shown that the zero-dispersion wavelength can be placed at any desired value by proper choice of the refractive index contrast and the fiber dimensions. The proposed coaxial line compares well with the known W-profiled line with respect to ease of manufacture and dispersion characteristics 相似文献
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A highly birefringent index-guiding photonic crystal fiber (PCF) with flattened dispersion and low confinement loss is proposed by introducing two small air holes with the same diameter in the core area. The fundamental mode field, birefringence, confinement loss, effective mode area and dispersion characteristic of the fibers are studied by the full-vector finite element method (FEM). Simulation results show that a high birefringence with the order of 10 -3 and a low confinement loss of 0.001 dB/km are obtained at 1550 nm. Furthermore, flattened chromatic dispersion from 1450 nm to 1590 nm is obtained. 相似文献
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《Microwave Theory and Techniques》1982,30(4):381-388
General propagation properties and universal curves are given for doubly clad single-mode fibers with inner cladding index higher or lower than outer cladding index, using the two parameters inner cladding/core radii ratio and inner cladding/core index differences ratio. LP01, LP11, and LP02 cutoff conditions are examined. It is shown that dispersion properties largely differ from the singly clad single-mode fiber case, leading to large new possibilities for low-loss dispersion-free fibers at any wavelength between 1.3 and 1.7 µm. 相似文献
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为了提高光子带隙型光子晶体光纤的温度灵敏度,提出了在纤芯环上并入高折射率液体圆柱的新结构,并利用全矢量有限元法对提出的结构进行了仿真,得到了温度对光纤有效折射率、纤芯能量和有效模面积等传输特性的影响。结果表明,随着温度的升高,光纤的有效折射率和有效模面积会减小,纤芯能量会增加,且零群速率色散点向短波长方向移动,尤其在短波长条件下光纤传输特性随温度变化趋势更加明显。该研究提高了光子带隙型光子晶体光纤传输特性的温度灵敏度,使其更加适合于温度传感方面的应用。 相似文献
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Photonic crystal fibers (PCFs) with elliptical air-holes located in the core area that exhibit high birefringence, low losses, enhanced effective mode area, and low chromatic dispersion across a wide wavelength range have been presented. The effects of bending on birefringence, confinement losses and chromatic dispersion of the fundamental mode of the proposed PCFs have been thoroughly investigated by employing the full vectorial finite element method (FEM). Additionally, localization of higher order modes is presented. Also, effects of angular orientation on bending loss have been reported. Significant improvement on key propagation characteristics of the proposed PCFs are demonstrated by carefully altering the desired air hole diameters and their geometries and the hole-to-hole spacing. 相似文献
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The field distribution of the TE mode and the dispersion relationships of the inner and outer slotted structures are given. The dispersion relationships are solved numerically and the dispersion curves are plotted. The interaction efficiency between electrons and the RF field in these structures is calculated numerically. Results are given, on the basis of which some conclusions concerning these kinds of structure are presented. 相似文献
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J. C. Hu P. Y. Su V. Lapeyronie S. L. Cheng M. Y. Lin L. J. Chen 《Journal of Electronic Materials》2004,33(10):1058-1063
Long-range order, uniform in size, and regular in shape two-dimensional (2-D) arrays of core-shell structure Au nanoparticles
have been synthesized. A reaction involving the displacement of the outer shells from tetraoctylammonium bromide (TOAB) to
dodecanethiol (DT) molecules was used to form Au@TOAB-DT nanoparticles at room temperature (RT). The displacement reaction
has used both superior size and shape control of Au@TOAB nanoparticles and uniform dispersion capability of Au@DT nanoparticles
to achieve an extraordinarily large in extent (3 μm×3 μm), regular nanoparticle lattice structure. From ultraviolet (UV)-visible
spectra, it was inferred that the interaction between the inner core and outer shell of Au@TOAB nanoparticles is weaker than
that of Au@TOAB-DT and Au@DT samples. As a result, the ability of the TOAB outer shell to protect the Au@TOAB nanoparticles
is weaker so that the system is more prone to agglomerate. On the other hand, the strong interactions between the inner core
and outer shell for Au@TOAB-DT and Au@DT nanoparticles led to a predominantly 2-D structure. 相似文献
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为了获得微结构光纤的平坦色散特性,设计了一种圆形排列的微结构光纤,其包层由周期分布的空气孔构成,通过有限元数值分析法对该微结构光纤基模的色散特性进行了数值仿真,研究了色散和纤芯圆孔尺寸以及波长的关系。结果表明:内外空气孔间距和直径对微结构光纤的色散曲线都有影响,但内包层大孔间距和第一圈小空气孔的直径对色散曲线的走向起决定作用。在内圈空气孔直径为3.1μm,其他空气孔直径为1.0μm,内圈空气孔中心间距为5μm,其他空气孔中心间距为4μm时,光纤在1.3μm波长的色散为19.5ps/(nm·km),在1.6μm波长的色散为26.5ps/(nm·km),在1.3~1.6μm波长范围内,其色散值变化范围为7ps/(nm·km)。 相似文献
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以单轴晶体为内包层的双包层光纤偏振特性研究 总被引:1,自引:3,他引:1
本文研究了以单轴晶体为内包层的双包层高双折射光纤的传输和偏振特性.在弱波导近似下,应用光波导理论,得出了o光与e光的色散方程及截止特性.通过计算机的模拟与分析,划分出了截止区、单模单偏振区、单模双偏振区及多模区;分析了单模单偏区和单模双偏区存在的条件;研究了单模双偏区两偏振模式的偏振色散特性.结果表明,几何参数S、光学参数Rx、Ry及外包层折射率η3对所划分的四个区域及所对应的偏振特性有着极为明显的影响.此结果为光纤保偏器的设计和应用高双折射单模光纤构成新型光纤传感器的设计提供了可靠的理论依据. 相似文献
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A symmetric five-layer slab waveguide with anisotropic and dispersive left-handed material (LHM) in the core and righthanded
material (RHM) in other layers is investigated. Through Maxwell’s equations and a transfer matrix method, the dispersion equations
for the TE oscillating guided modes are obtained. Under consideration of two extremely anisotropic cases, some mode dispersion
curves are plotted. The zero-order TE oscillating guided mode exists. Meanwhile, with the increase of mode number, their dispersion
curves move to left or right, corresponding to positive or negative dielectric permittivity and magnetic permeability in the
longitudinal direction. Besides, as the core thickness increases, mode dispersion properties change and three propagation
properties appear: positive group velocity, negative group velocity and zero group velocity. The negative group velocity indicates
the characteristics of the left-handed materials, and the zero group velocity implies that electromagnetic waves are trapped
in the waveguide completely. 相似文献
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介绍了一种带正色散的单模光纤,用来均衡常用于海底光缆中的非零色散位移光纤的负色散。这种光纤类似于常规单模光纤(G.652光纤),但具有较低的衰减和较小的宏弯损耗。由于这种光纤应用常规的掺锗纤芯和纯SiO2包层,与目前常用的纯SiO2纤芯和掺氟包层的色散均衡光纤相比,在成本上具有较大的优越性。 相似文献