共查询到20条相似文献,搜索用时 198 毫秒
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研究了基于结构性改变的光子晶体光纤光栅的热激法制备工艺,理论分析了此种工艺的成栅原理,采用热传导理论和有限元法研究了制备过程中光子晶体光纤中的温度场分布,以及包层空气孔结构和激光参数对成栅效果的影响.研究结果表明,利用光子晶体光纤包层空气孔周期性塌缩可以形成光栅;采用两点热激法时,能够实现能量在光纤径向均匀分布,轴向近似于高斯分布;包层气孔结构加速了成栅过程,相同光斑尺寸下,光纤塌缩所需激光功率随气孔层数和气孔半径的增大而减小;最后,对包层空气孔结构为1层到7层的光子晶体光纤热激过程进行仿真,得到了空气填
关键词:
光纤光栅
光子晶体光纤
热激法
有限元法 相似文献
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G. Amouzad Mahdiraji Desmond M. Chow S. R. Sandoghchi F. Amirkhan E. Dermosesian Kwok Shien Yeo 《Fiber and Integrated Optics》2014,33(1-2):85-104
AbstractThe fabrication process of photonic crystal fibers based on a stack-and-draw method is presented in full detail in this article. In addition, improved techniques of photonic crystal fiber preform preparation and fabrication are highlighted. A new method of connecting a handle to a preform using only a fiber drawing tower is demonstrated, which eliminates the need for a high-temperature glass working lathe. Also, a new technique of modifying the photonic crystal fiber structural pattern by sealing air holes of the photonic crystal fiber cane is presented. Using the proposed methods, several types of photonic crystal fibers are fabricated, which suggests potential for rapid photonic crystal fibers fabrication in laboratories equipped with and limited to only a fiber drawing tower. 相似文献
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Tomoharu Hasegawa 《Optics Communications》2012,285(19):3939-3944
The process of design and fabrication of bismuth-silicate photonic crystal fiber (Bi-PCF) is reported. The Bi-PCF was fabricated by stack and draw method. This is the first trial of the fabrication of photonic crystal fiber made of bismuth-based glass with stack and draw method. The Bi-PCF structure was designed to reduce group-velocity-dispersion (GVD) in a plausible process. Thermal properties of the glass are investigated to establish the fabrication process. The applying pressure and pumping in fiber preform preparation were effectively utilized to control the air-hole diameter and arrangement. The fabricated Bi-PCF shows the well reduced GVD as the numerical calculation predicted. Fusion splicing between Bi-PCF and SMF-28 was also demonstrated. 相似文献
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D. Nodop S. Linke F. Jansen J. Limpert A. Tünnermann L. Rindorf 《Applied physics. B, Lasers and optics》2008,92(4):509-512
We report for the first time, to the best of our knowledge, on the fabrication and characterization of CO2-laser written long-period gratings in a large-mode area photonic crystal fiber with a core diameter of 25 μm. The gratings
have low insertion losses (<1 dB) and high attenuation (>10 dB) at the resonant wavelengths, making them particularly interesting
for high power applications. 相似文献
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Fabrication of fiber-embedded multi-core photonic crystal fibers 总被引:2,自引:0,他引:2
A novel fabrication method of multi-core photonic crystal fibers is proposed on the basis of a fiber-embedded technique. A taper tower is used to modify the structures of the fiber preform, and four steps of fiber fabrication and different structures of fiber samples are given. The mode structures and beating characteristics of a photonic crystal fiber sample with two successive cores are investigated in detail with the help of a supercontinuum light source, a charge-coupled device (CCD) camera, and an optical spectrum analyzer. The test results show a clear beating phenomenon between two orthotropic polarization modes with a 2.8-nm peak interval in wavelength. 相似文献
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Photonic crystal waveguide sampled gratings (PCWSG) are proposed to realize multi-channel optical filter in a photonic crystal (PC) waveguide. The reflection characteristics of the filter are analyzed by using the coupled-mode theory (CMT) together with transfer-matrix method (TMM). It is shown that the reflection spectrum of the filter exhibits a group of reflection peaks, which are distributed with equal frequency spacing within the photonic crystal bandgap (PBG). The theoretically calculated results are numerically verified by using two-dimensional (2D) finite-difference time-domain (FDTD) method. 相似文献
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O. Frazo J.L. Santos F.M. Araújo L.A. Ferreira 《Laser \u0026amp; Photonics Reviews》2008,2(6):449-459
A review of optical fiber sensing demonstrations based on photonic crystal fibers is presented. The text is organized in five main sections: the first three deal with sensing approaches relying on fiber Bragg gratings, long‐period gratings and interferometric structures; the fourth one reports applications of these fibers for gas and liquid sensing; finally, the last section focuses on the exploitation of nonlinear effects in photonic crystal fibers for sensing. 相似文献
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光子晶体光纤具有特殊的导光机制和结构可调性,可以产生奇异的色散特性及高非线性,为非线性光纤光学领域的研究提供了新的条件。受多种非线性光学效应的共同作用,在不同泵浦光脉冲参数条件下,不同结构参数及传输特性的光子晶体光纤能产生丰富的非线性光谱。利用分步傅里叶方法求解非线性薛定谔方程,模拟飞秒激光脉冲在光子晶体光纤中的传输过程,获得输出光谱与入射光脉冲参数(泵浦光峰值功率P、泵浦光波长λ、光脉冲形状、光脉冲宽度TFWHM)、光纤结构参数(孔间距Λ、空气填充比d/Λ、光纤长度z)、传输特性(色散、非线性系数)的关系,分析拉曼孤子、色散波、自相位调制等非线性效应产生的光谱特性。利用光子晶体光纤包层节区进行非线性光学实验研究,获得了孤子波和色散波的宽带光谱输出。理论分析与实验测量的光谱中都包括了波长0.5 μm附近可见光波段的蓝移色散波、0.82 μm波段的剩余泵浦光、1.1 μm波段的孤子波、2 μm附近的红移宽带色散波。理论分析与实验测量结果一致,阐明光子晶体光纤中非线性光谱产生的物理原理,实现了对宽带光谱的可控输出,为高非线性光子晶体光纤的结构设计、制备及非线性光谱的应用研究奠定基础。 相似文献
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基于由光子晶体光纤飞秒激光器产生的高重复频率飞秒激光搭建了飞秒激光微加工系统,利用LabVIEW编写程序精密控制三维移动平台的移动路径和高速快门,在加工功率为1.5W、移动速率为1mm/s时,利用直写技术在无胶铬版上得到了微米量级的任意形状的平面衍射光栅。利用CCD相机对光栅制备过程进行实时监视,保证了光栅的加工质量。制备的光栅在显微镜下观察,条纹边缘清晰、线纹粗细均匀。使用He-Ne激光照射加工的光栅,可以获得清晰、稳定、与理论符合很好的夫琅和费(Frauhofer)衍射图样,显示了所加工的光栅具有良好的光学性能。实验结果也表明了光子晶体光纤飞秒激光在光栅制作过程中所具备的良好的加工性能。 相似文献
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We report the demonstration of rewritable self-assembled long-period gratings in air-core photonic bandgap fibers. The long-period gratings are written by filling the air-core region of the fiber with a solution containing polystyrene microspheres. The microspheres are self-assembled into a periodic structure as the liquid inside the fiber evaporates, forming the long-period grating. The formed grating can then be easily erased for rewriting purposes by connecting the end of the fiber to a microfluidic pump through a microfluidic channel and washing out the microparticles with an appropriate liquid. The same microfluidic system can also be used to fine control the writing process of the gratings. This technique creates possibilities for writing various different filtering functions in air-core photonic bandgap fibers by varying the composition and/or the shape of the used microparticles. The presented technique is potentially applicable to solid-core photonic crystal fibers as well. 相似文献
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We extend the improved effective index method (IEIM) to analyze the cladding mode of the photonic crystal fiber (PCF) and to predict cladding mode coupling in gratings. By introducing a new step-index fiber model for the PCF, the cladding mode coupling between a LP01 core mode and HE11 cladding mode in long-period gratings formed in PCF is accurately predicted by the IEIM. The fiber model works well for the PCF used here not only in predicting resonant mode coupling, but also in analyzing core and low-order cladding modes. 相似文献
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A method of designing photonic crystal grating slow-wave circuit for Ribbon--Beam microwave travelling wave amplifiers 下载免费PDF全文
A method of designing a photonic crystal grating slow-wave circuit in which
the cylinders of the 2D photonic crystals dot on a cross-sectional plane is
established by calculating the band structures of the 2D photonic crystals,
and the eigenfrequency of the equivalent waveguide grating. For calculating
the band structures, the eigenvalue equations of the photonic crystals in
the system of photonic crystal grating slow-wave circuit are derived in a
special polarization mode. Two examples are taken to show the method. The
design result is validated by the scattering parameters of the same circuit.
The result indicates that there exists no photonic band gap if the metal
gratings do not extend into the photonic crystals; the design of the circuit
without the metal gratings extending into the photonic crystals is less
flexible than that with the metal gratings extending into the photonic
crystals. 相似文献
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Grating resonances in air-silica microstructured optical fibers 总被引:13,自引:0,他引:13
We report what is believed to be the first demonstration of optical fiber gratings written in photonic crystal fibers. The fiber consists of a germanium-doped photosensitive core surrounded by a hexagonal periodic air-hole lattice in a silica matrix. The spectra of these gratings allow for a detailed characterization of the fiber. In particular, the gratings facilitate coupling to higher-order leaky modes. We show that the spatial distribution and the effective index of these modes are determined largely by the design of the lattice and that the grating spectra are unaffected by the refractive index surrounding the fiber. We describe these measurements and corresponding simulations and discuss their implications for the understanding of such air-hole structures. 相似文献
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Maciej Antkowiak Rafał Kotyński Krassimir Panajotov Francis Berghmans Hugo Thienpont 《Optical and Quantum Electronics》2006,38(4-6):535-545
We analyze theoretically the coupling properties of Bragg gratings written in highly birefringent photonic crystal fibers
with doped core and show how they can be tuned by the parameters of a microstructured fiber. We apply the coupled mode theory
combined with a fully vectorial mode solver based on the plane-wave method. The results indicate large differences in interaction
with the grating for the two linearly polarized fundamental modes. We show fiber designs, which provide single-mode operation
with high birefringence and at the same time a high coupling efficiency of the grating. Such features can be used in fiber
sensors, fiber laser configurations or to introduce a polarization dependent feedback in a long external cavity system with
a semiconductor laser. 相似文献
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Tunable fiber gratings fabricated in photonic crystal fiber by use of mechanical pressure 总被引:1,自引:0,他引:1
The mode-coupling properties of tunable long-period fiber gratings (LPGs) formed in photonic crystal fibers (PCFs) are presented. The mode coupling from the fundamental core mode to a cladding mode of a PCF is obtained by use of periodic mechanical pressure. The strength and the wavelength of the resonant peak are tuned by adjusting the grating period and the pressure applied on the PCF. Contrary to the conventional fiber case, the resonant wavelength of the PCF LPG is decreased by increasing the periodicity. 相似文献