共查询到20条相似文献,搜索用时 343 毫秒
1.
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
2.
The finite difference waveguide mode solution method, which has been popularly employed in the study of waveguide modes on various optical and dielectric waveguides, is utilized to calculate the modal characteristics of photonic crystal fibers (PCFs) and planar photonic crystal waveguides and the band diagrams of two-dimensional photonic crystals. Vector guided modes on both PCFs based on the total internal reflection guiding mechanism ('holey fibers') and those resulting from photonic band gap effect are accurately computed, with their effective indexes and field distributions compared with other methods. Calculated dispersion of a single-core holey fiber and coupled-power behavior of a two-core holey fiber are found to agree with measured results. For applications to band diagram calculation and planar photonic crystal waveguide analysis, the finite difference scheme is modified simply by imposing suitable periodic boundary condition. Numerical results for air-column crystals and dielectric-rod crystals are both found to agree well with calculations using other methods. 相似文献
3.
利用多极法对八边形光子晶体光纤的色散补偿特性进行数值模拟,分析了结构参数变化对色散补偿特性的影响;计算了具有相同参数的六边形结构光子晶体光纤的色散系数和非线性系数;研究表明八边形光子晶体光纤比六边形结构的光子晶体光纤的大负色散特性明显提高,非色散系数低,更有利于进行色散补偿.因此,本文设计了一种新型的八边形色散补偿光纤,在λ=1.55μm时色散值为-1434.9ps·nm-1·km-1,色散斜率为-4.6338ps·nm-2·
关键词:
光子晶体光纤
多极法
色散斜率
色散补偿 相似文献
4.
5.
6.
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
7.
提出了一种用于分析椭圆孔光子晶体光纤的正交函数模型.发展了一种新型超格子的构造方法,将光子晶体光纤的横向介电常数表示为两种周期性结构叠加,这两种周期性结构分别用余弦函数展开;同时将横向电场以Hermite-Gaussian函数展开.利用正交函数的性质,将全矢量波动方程转化为矩阵本征值问题,求得两偏振模式传输常数.利用此模型可以研究圆孔及椭圆孔光子晶体光纤的模式特性、色散特性、偏振特性等.
关键词:
光子晶体光纤
超格子
正交函数
本征值问题 相似文献
8.
一种阶梯结构的色散平坦光子晶体光纤的研究 总被引:4,自引:1,他引:3
以多极法理论为基础,提出了一种阶梯结构的光子晶体光纤.通过改变其内四层的三个结构参量(内两层孔孔径,外两层孔孔径和孔间距),实现色散绝对值在1.1~1.8μm的波段内变化仅为0.05~2 ps/(km·nm)的平坦甚至超平坦的特性.在此情况下对其有效模场面积进行数值模拟,充分展示了达到色散平坦和超平坦时,相对于传统光子晶体光纤,此种结构的光纤对芯区内光场的局域能力有很大程度的增强,其有效模场面积可仅为传统光子晶体光纤的1/30.最后,经过大量的数值计算和理论分析,归纳出若要此种阶梯结构的光纤在1.1~1.8μm的波段内达到色散平坦甚至超平坦特性的设计依据. 相似文献
9.
Tatsuya Kinjo Yoshinori Namihira Kazuya Arakaki Shubi F. Kaijage S. M. Abdur Razzak Feroza Begum Hiroki Higa Shinya Nozaki Nianyu Zou 《Optical Review》2010,17(2):66-73
In this paper we present the design of a modified hexagonal photonic crystal fiber (PCF) having high birefringence and a near-zero
flattened dispersion. Using the finite-difference method (FDM), it is shown that the proposed multiple Gedoped core hexagonal
PCF exhibits a high birefringence of order 10−3 and a nearly zero flattened dispersion in the optical coherence tomography (OCT) waveband. In addition, the proposed PCF
has a confinement loss of less than 10−8 dB/m at 1.06 μm. PCFs with such properties are considered suitable for both endoscopic OCT and other experimental setups
employing 1.06 μm lasers. 相似文献
10.
利用矢量有效折射率方法对光子晶体光纤(PCF)的色散补偿特性进行了数值模拟,研究发现通过调节光子晶体光纤包层的空气穴节距或空气穴大小可以灵活地设计光子晶体光纤的色散系数D、色散斜率Dslope以及κ值,可以设计在波长1.55μm附近具有较大绝对值的正常色散和负色散斜率的色散补偿光子晶体光纤,使光通信中的普通单模光纤(G.652)或非零色散位移光纤(G.655)在1.55μm低损耗窗口得到较好的色散补偿.数值模拟和分析表明色散补偿光子晶体光纤的研制具有很大的发展潜力.
关键词:
光子晶体光纤
色散
色散斜率
色散补偿 相似文献
11.
When using normalized dispersion method for the dispersion design of photonic crystal fibers (PCFs), it is vital that the group velocity dispersion of PCF can be seen as the sum of geometrical dispersion and material dispersion. However, the error induced by this way of calculation will deteriorate the final results. Taking 5 ps/(km.nm) and 5% as absolute error and relative error limits, respectively, the structure parameter boundaries of PCFs about when separating total dispersion into geometrical and material components is valid are provided for wavelength shorter than 1700 nm. By using these two criteria together, it is adequate to evaluate the simulated dispersion of PCFs when normalized dispersion method is employed. 相似文献
12.
A kind of highly birefringent quinquangular-core photonic crystal fiber(Q-PCF) structure is proposed and analyzed by full-vector finite element method(FEM) . The modal field,effective index,and birefringence properties are investigated. From the numerical results,it is found that the birefringence of the new polarization-maintaining PCFs is at least five times larger than that of the standard highly birefringent hexagonal PCFs(H-PCFs) with the same hole pitch,hole diameter,and whole hole area as that of the new PCFs at 1 550 nm. Moreover,the modal field of the new PCFs could be better restricted than that of the standard highly birefringent H-PCFs;hence,the loss of fibers could be reduced. 相似文献
13.
We present an analytical procedure to compute the first derivatives of the propagation constants with respect to several structural parameters in photonic crystal fibers (PCFs). From them we can easily evaluate the same derivatives of other directly related magnitudes. The above derivatives provide the trend of the magnitude at issue, which allows us to take advantage of a gradient-based algorithm to shape the properties of the guiding structure. In this way we implement an optimization process to carry out real inverse design in PCFs. We focus our attention on designing PCFs with a specific chromatic dispersion behavior. Likewise, the same approach makes it possible to analyze their fabrication tolerances. 相似文献
14.
In this paper we present an analytical formula for bending loss oscillations in photonic crystal fibers (PCFs). We follow the approach originally adopted for conventional double-clad fibers and show that it can be applied to PCFs by substituting the structural parameters of the conventional fiber by their PCF counterparts. We then examine the spectral dependence of the critical bending radius and the position of the first order loss peak as a function of structural parameters of the PCF cladding such as the fill factor and the number of hole rings. Finally, we evaluate the precision of the analytical model by comparing the results to finite element calculations for a selection of PCF geometries. 相似文献
15.
Applications of Nonlinear Effects in Highly Nonlinear Photonic Crystal Fiber to Optical Communications 总被引:4,自引:0,他引:4
Unique dispersion characteristics and enhanced nonlinearity make the small-core photonic crystal fiber (PCF) an ideal candidate for nonlinear optical devices to telecommunication applications. Some technical reasons behind great research interest of highly nonlinear PCFs in optical communication components are reviewed. Nonlinear effects in highly nonlinear PCFs and their research progress are presented. Several typical applications including WDM sources, optical amplification, optical switching, wavelength conversion, optical regeneration and all-optical demultiplexing etc are introduced, together with state-of-the art performances. Some new possible applications and future prospects are discussed. 相似文献
16.
在采用阶跃有效折射率模型研究光子晶体光纤的可行性方面,提出了将普通单模光纤、色散位移光纤、色散平坦光纤作为一定极限条件下的折射率引导型光子晶体光纤特例的观点.通过编程计算,并与文献报道的实验数据对比,表明应用本模型可以揭示光子晶体光纤所具有的奇异的色散机理.特别是应用本模型具有更快的计算速度.还用本模型分析了空气孔直径、周期及芯径对色散特性的影响.
关键词:
折射率引导型光子晶体光纤
阶跃有效折射率模型
色散 相似文献
17.
18.
Highly birefringent elliptical-hole photonic crystal fiber with squeezed hexagonal lattice 总被引:3,自引:0,他引:3
Yue Y Kai G Wang Z Sun T Jin L Lu Y Zhang C Liu J Li Y Liu Y Yuan S Dong X 《Optics letters》2007,32(5):469-471
We propose a novel polarization-maintaining index-guiding photonic crystal fiber (PCF). It is composed of a solid silica core and a cladding with squeezed-hexagonal-lattice elliptical air holes. Using a full-vector finite-element method, we study the modal birefringence of the fundamental modes in such PCFs. Numerical result shows that very high modal birefringence with a magnitude of the order of 10(-2) around 1550 nm has been obtained. Furthermore, large normal dispersion appears over a wide range of wavelengths in both orthogonal polarizations. 相似文献
19.
A simple design procedure is used to generate photonic crystal fibers (PCFs) with ultra-flattened chromatic dispersion. Only four parameters are required, which not only considerably saves the computing time, but also distinctly reduces the air-hole quantity. The influence of the air-hole diameters of each ring of hexagonal PCFs (H-PCF, including 1-hole-missing and 7-hole-missing H-PCFs), circular PCFs (C-PCF), square PCFs (S-PCF), and octagonal PCFs (O-PCF) is investigated through simulations. Results show that regardless of the cross section structures of the PCFs, the 1st ring air-hole diameter has the greatest influence on the dispersion curve followed by that of the 2nd ring. The 3rd ring diameter only affects the dispersion curve within longer wavelengths, whereas the 4th and 5th rings have almost no influence on the dispersion curve. The hole-to-hole pitch between rings changes the dispersion curve as a whole. Based on the simulation results, a procedure is proposed to design PCFs with ultra-flattened dispersion. Through the adjustment of air-hole diameters of the inner three rings and hole-to-hole pitch, a flattened dispersion of 0±0.5 ps/(nm·km) within a wavelength range of 1.239 – 2.083 μm for 5-ring 1-hole-missing H-PCF, 1.248 – 1.992 μm for 5-ring C-PCF, 1.237 – 2.21 μm for 5-ring S-PCF, 1.149 – 1.926 μm for 5-ring O-PCF, and 1.294 – 1.663 μm for 7-hole-missing H-PCF is achieved. 相似文献
20.
Kazuya Miyagi Yoshinori Namihira S. M. Abdur Razzak Shubi F. Kaijage Feroza Begum 《Optical Review》2010,17(4):388-392
We have demonstrated that the correction factor k
n
= A
eff/(πw
2), where ω = MFD/2 (MFD: mode field diameter), is above 1.20 for photonic crystal fibers (PCFs) with structural parameters in the range
of d/Λ ≅ 0.40 to 0.90 (d/Λ ratio of hole diameter d and pitch Λ). By using the far-field scanning (FFS) technique and the finite difference method, the results of experimental
measurements and numerical simulations differed by only 0.9 to 3.0% for two types of PCFs. The finding that k
n
≠ 1.0 for PCFs indicates that their electrical field distribution is non-Gaussian and cannot be determined by assuming a
conventional step-index distribution for PCFs. It was also found that the ITU-T Petermann II definition is the most suitable
for MFD measurements of PCFs with non-Gaussian distribution. 相似文献