共查询到20条相似文献,搜索用时 0 毫秒
1.
The modal properties of all solid microstructured-core optical fibers are investigated in this article. The core of which is composed of a few rings of high-index rods. The cutoff wavelength of the proposed fibers are investigated by applying the effective index model and confirmed by a full-vectorial finite element method with perfect matched layer boundary conditions. In addition, the dependence of mode areas on the period, diameter and refractive index of high-index rods are explored. In particular, numerical simulations demonstrate the possibility of single-mode guidance with the mode area extending to 11,900 μm2 at the wavelength of 1.55 μm in the proposed fiber. 相似文献
2.
A novel kind of single-mode large-mode-area optical fiber is presented in this paper. The proposed fiber core is composed of high-index central rod and the surrounding multilayer rings. The mode characteristics are discussed considering the fiber structure parameters. The calculation results show that the proposed fiber possesses extreme large mode area of 2975 μm2 with single mode operation at the wavelength of 1.08 μm. Even larger mode area of the complex ring core fiber with single mode output can be achieved by coiling the fiber, due to the significant difference of bending loss between the fundamental mode and the higher-order transverse modes. Such fibers are expected to find applications in the field of fiber lasers and amplifiers. 相似文献
3.
Md. Selim Habib Md. Samiul Habib S.M. Abdur Razzak Yoshinori Namihira M.A. Hossain M.A. Goffar Khan 《Optik》2013
This paper presents a microstructure optical fiber for dispersion compensation in a wide range of wavelengths. The finite-element method with perfectly matched absorbing layers boundary condition is used to investigate the guiding properties. The designed novel dispersion compensating fiber shows that it is possible to obtain a larger negative dispersion coefficient of about −130 to −360 ps/(nm km), better dispersion slope compensation, better compensation ratio, and lower confinement losses less than 10−2 dB/km in the entire telecommunication (1400–1600 nm) band by using a modest number of design parameters and very simple cladding design. 相似文献
4.
提出了一种新型双空气孔多芯-双模-大模场面积光纤结构, 计算了其模场分布、基模有效面积及弯曲损耗特性, 分析了各结构参量对其有效折射率及有效面积的影响. 这种结构在增大有效面积的同时使得二阶模的TE01, TM01模截止, 实现双模传输, 基模有效面积约为1044 μm2.调整其结构参量, 甚至可以达到单模传输.这种结构制作简单、设计灵活, 可用于高速大容量无源光纤及有源器件中.合理设计各结构参量, 可以使有效面积达到3512 μm2甚至更高, 从而满足光通信领域中大容量、高功率传输等实际应用的需求.
关键词:
多芯光纤
双模
大模场面积
弯曲损耗 相似文献
5.
Microstructure optical fibers with flat-top fundamental mode are first proposed by introducing a low-index inner core into the core of index-guiding microstructure optical fibers. The design guidelines and characteristics of beam-shaping microstructure optical fibers are demonstrated. The interrelationships of inner-core index with laser wavelength, air hole diameter and size of inner core are investigated. The influence of the relative size of inner core on the spatial profile of the fundamental mode is demonstrated. Moreover, sensitivity of the flat-top fundamental mode profile from the slight change of the optimum inner-core index value is studied. Starting from these results we deduce that it is possible to fabricate beam-shaping microstructure fibers with nowadays technique. 相似文献
6.
Based on the methods to design the three-mirror reflective system, the aberrations formulae for the four-mirror optical reflection system have been deduced and presented for the first time. The diversity of parameter ranges for the designed system for different structures is also studied to select the parameters to obtain the practicable initial structure. Example designs with proposed methods are presented here and their performance evaluations demonstrate that the image qualities of these examples attain the diffraction limits. 相似文献
7.
A large mode area multicore photonic crystal fiber with a flattened fundamental mode is proposed in this paper. Another two kinds of single core fibers are also presented as comparison. The modal characteristics such as effective mode area and confinement loss are investigated using the finite element method. Numerical results show that a combination of flattened fundamental mode, large mode area and ultralow loss is obtained in the multicore fiber by introducing higher refractive index in the core region. 相似文献
8.
In this paper, we have investigated the mutual and self coupling characteristics of directional couplers using two individual gain guided and index antiguided fibers, which can deliver robust single mode operation with large mode area, respectively owing to the combined adequately large gain coefficients in the core; Some interesting and distinguishing properties from conventional index guided fiber couplers are obtained that: The variations of coupling coefficients are complex-valued and spatially damping oscillated, but not exponential-like decreasing as conventional index guided couplers. 相似文献
9.
Wang Xiangru Xiong Caidong Wen Xia Qiu Qi Luo Juanyan Deng Hao Xie Wen 《Optics Communications》2010,283(1):44-48
With the purpose of uniform gain coefficient along the axial direction in the core of gain guided and index anti-guided fiber, a new kind of side-pump scheme by wrapping particularly treated fibers around the central GGIAG fiber is reported in this paper. According to leakage mode analysis on wrapped fiber and numerical simulation on this pumping structure having ytterbium doped central fiber and conventional wrapped side fiber, we find this kind of pump scheme can improve the uniformity of gain coefficient along the fiber direction, and also, it can support multi channels of pumping sources by adding more side fibers to improve the total effective incident pumping power. 相似文献
10.
We propose a three-dimensional (3D) finite-difference time-domain (FDTD) method to analyze the pulse propagation characteristics in microstructured optical fibers (MOFs). The computation domain size is greatly reduced by adopting the technique of moving problem space. The propagating pulse is virtually held in the buffer cell of the problem space as simulation continues. This method is capable to investigate the temporal evolution of the propagating pulse. Spectral information can be obtained by Fourier analysis. As an example, the influence of the kerr nonlinearity on the optical pulse propagation in a Lorentz dispersive MOF is demonstrated. The model is also used to simulate the nonlinear interactions between the pump spectral broadening and third harmonic generations in a highly nonlinear fused silica nanowire with good agreement with the generalized nonlinear envelop equation (GNEE) model. 相似文献
11.
Using the time-independent power flow equation, we have examined the mode coupling caused by intrinsic perturbation effects in step-index As2Se3 chalcogenide-glass multimode optical fiber in the mid-infrared region. Results show that the coupling length where the equilibrium mode distribution is achieved depends on the wavelength and is of the order of kilometers. 相似文献
12.
13.
In this paper, using the fully vectorial effective index method (FVEIM), dependence of the refractive index of fundamental mode, mode field diameter and normalized frequency of the photonic crystal fiber on geometrical parameters of fiber are investigated. Simulations show that the normalized frequency of the photonic crystal fiber increases gently with increase of the air filling factor. Range of parameters in which erbium doped photonic crystal fiber is single mode at both the pump wavelength and the signal is determined. Wavelength dependence of the normalized frequency implies that single mode region of the signal in the case of using dopants such as ytterbium or erbium is significantly (about 1.6 times) more than the pump. In addition, it is shown that by changing dopant material to obtain a higher gain for an optimum set of geometrical parameters, no considerable change in the area of single mode occurs. 相似文献
14.
15.
We propose a method for calculation of the bandgaps in the cladding of hollow-core photonic crystal fibers, based on the Floquet
theorem. The effectiveness of the approach is confirmed by estimates of the effect of the number of air channels in the cladding
on attenuation of the fiber modes due to mode energy leakage from the core. We have studied the conditions for the existence
of eigenmodes in the indicated fibers.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 311–320, March–April, 2009. 相似文献
16.
大模场光子晶体光纤在高功率激光传输、光纤放大器、光纤激光器中的广泛应用, 使其受到研究者的广泛关注.硫系玻璃在红外波段(1–20μm)具有优良透过性能, 且具有折射率高(2.0–3.5)、声子能量低(小于350 cm-1)、 组分可调等特性, 成为制备红外光纤的理想材料. 本文设计一种基于Ge20Sb15Se65硫系玻璃基质的新型单模传输、低损耗、超大模场面积光子晶体光纤结构, 经理论验证其在λ =10.6 μm处基模限制损耗远低于0.1 dB/m, 高阶限制模损耗大于2 dB/m, 模场面积约为13333 μm2.
关键词:
硫系玻璃
大模场面积
红外光子晶体光纤
结构设计 相似文献
17.
In this paper, a refractive index profile design enabling us to obtain a flat modal
field around the fibre centre is investigated. The theoretical approach for
designing such multilayer large flattened mode (LFM) optical fibres is presented. A
comparison is made between the properties of a three-layer LFM structure and a
standard step-index profile with the same core size. The obtained results indicate
that the effective area of the LFM fibre is about twice as large as that of the
standard step-index fibre, but the LFM fibre has less effective ability to filter
out the higher order modes than the standard step-index fibre with the same bending
radius. 相似文献
18.
Theoretical analysis of optical force density distribution inside subwavelength-diameter optical fibers 下载免费PDF全文
We investigate the microscopic optical force density distributions respectively inside a subwavelength-diameter(SD)fiber with flat endface and inside one with oblique endface by using a finite-difference time-domain(FDTD) method.Optical force density distributions at the fiber endfaces can now be readily available. The complete knowledge of optical force density distributions not only reveal features regarding the microscopic near-field optomechanical interaction, but also provide straightforward explanations for the sideway deflections and other mechanical motions. Our results can provide a useful reference for better understanding the mechanical influence when light transports in a microscale or nanoscale structure and for developing future highly-sensitive optomechanical devices. 相似文献
19.