C-lens准直器回波损耗的理论计算与分析

用矩阵光学和几何光学的方法计算了C-lens准直器的回波损耗,分析了影响回波损耗的各主要因 素,并绘出了回波损耗对各影响因素的响应曲线,对C-lens光纤准直器的设计和优化具有一定指导意义.     

实心光子带隙限制光纤泄漏损耗的研究

芯区向下掺杂的实心蜂窝形光子晶体光纤可以通过光子带隙限制(PBG)导光,本文采用多极方法研究了这种实心PBG光子晶体光纤的泄漏损耗,研究表明在气孔直径与气孔周期的比为0.8时,仅需84个气孔,就能使这种实心PBG光子晶体光纤的泄漏损耗降低到10^-2dB/km.本文的模拟结果可用于实心PBG光子晶体光纤的实际应用.     

光子带隙型光子晶体光纤

光子晶体光纤（PCF）有着许多奇异的特点和广泛的应用前景。目前,光子晶体光纤的技术发展很快,其潜在应用不断被发掘出来。文章简要分析了光子带隙（PBG）型PCF的导光机制,介绍了它的典型结构、制作工艺和PBG的形成机理。探讨了其在光通信中的应用。     

带隙型光子晶体光纤的研究进展

阐述了带隙型光子晶体光纤(PBG-PCF)的发展历史、导光机制和三角形结构光子带隙光纤的特点;较全面地讨论了带隙型光子晶体光纤的特性;重点讨论了现有带隙型光子晶体光纤损耗较大的原因及进一步减小损耗的方法.     

C-lens准直器回波损耗的理论计算与分析

用矩阵光学和几何光学的方法计算了C-lens准直器的回波损耗，分析了影响回波损耗的各主要因素，并给出了回波损耗对各影响因素的响应曲线，对C-lens光纤准直器的设计和优化具有一定指导意义。     

四方格子全固光子带隙光纤带隙特性研究

基于平面波展开法,对四方格子全固光子带隙光纤带隙随结构的变化特性进行了数值模拟,并与具有相同结构参数三角格子全固光子带隙光纤进行了比较,数值结果表明带隙的位置由高折射率棒的结构参数决定,而与高折射率棒的排列方式和棒之间的间距无关,这一结果与反谐振效应非常吻合。最后对理想和实际拉制出的四方格子的全固态光子带隙光纤的带隙进行了比较,得出了在设计光纤时,应利用较低的带隙的结论。     

光子带隙型光子晶体光纤的研究

实验证明,空心的空气-石英光子晶体光纤的纤芯可以局域光,并在理论的基础上,得到光子带隙存在的条件,特定的波带受到限制并沿光纤传导;与每一个波带相对应的光子晶体包层中出现一个完全的二维光子带隙,随着空气填充率的增加,光子带隙的相对大小也会随之变大,而且当减小空气孔尺寸时,光子带隙将被抑制。采用透射谱法在红外波段对带隙型光子晶体光纤进行测量,通过比较光纤的透过谱与光源的光谱,确定是否存在光子带隙。     

光子带隙型光子晶体光纤研究与应用

带隙型光子晶体光纤(PBG-PCF)因其独特的性能,在各个领域都有着广泛的应用前景.文章阐述了带隙型光子晶体光纤的导光机制,并将带隙型光子晶体光纤分为空芯光子晶体光纤和全固态带隙型光子晶体光纤两类,较全面地讨论了这两类光纤的特性及其应用.     

复合蜂巢晶格光子晶体光纤的带隙结构研究

提出了基于复合蜂巢晶格的光子晶体光纤。该光纤包层蜂巢结构每个单元内部包含 有一层空气孔,它们形成另一个蜂巢结构。采用平面波展开法研究了这种复合结构的光子晶体光纤的带隙结构随内层蜂巢晶格参数的变化规律。研究发现,内层晶格位置存在一个临界值,在该值以下,光纤的带隙减小。同时得到了一些晶格参数使得次带隙得到抑制,而主带隙大小基本不变。     

光子带隙光纤的奇异特性和应用

描述了三个很具特色的结构特例：复式蜂窝状、薄壁六角形和多层环状光子带隙光纤,同时介绍了它们的光学特性,包括带隙、损耗和色散。最后介绍了光子带隙光纤在传输高能量脉冲、大功率光孤子和光纤激光器中的应用。     

空芯光子晶体光纤损耗的研究

为了研究反共振纤芯壁对空芯光子晶体光纤限制损耗和散射损耗的影响,利用全矢量有限元法对所设计的具有不同纤芯壁和纤芯半径的空芯光子晶体光纤进行仿真,得到了3种纤芯壁在不同纤芯半径时的有效折射率、限制损耗和芯内功率分数随波长变化的曲线。由数值模拟结果可知,纤芯壁采用T=3的环形反共振层和椭圆反共振层设计时,限制损耗降低了约两个数量级,芯内功率分数在通信波段提高了13%。结果表明,这两种设计可以有效降低空芯光子晶体光纤的限制损耗和散射损耗。     

Confinement loss and nonlinearity analysis of air-guiding modified honeycomb photonic bandgap fibers

Air-guiding photonic bandgap fibers based on a modified honeycomb lattice have been numerically investigated through the finite element method. Results confirm that an extra hole in the unit cell of a honeycomb lattice can be exploited to enlarge the photonic bandgap, allowing air-guiding with confinement losses lower than 0.1 dB/km and nonlinear coefficient lower than 3.5/spl middot/10/sup -3/(W/spl middot/km)/sup -1/ at 1.55 /spl mu/m.     

Research on highly nonlinear photonic bandgap fibers

Since thefirst photonic crystal fiber (PCF) wasfabri-cated by Knight J C and his colleagues[1]at 1996 ,thistype of fibers ,consisting of a central defect region sur-rounded by multiple air holes running alongits length,has been the subject of much interes…     

Confinement losses in air-guiding photonic bandgap fibers

The wavelength dependence and the structural dependence of confinement losses in air-guiding photonic bandgap fibers (PBGFs) are, for the first time, investigated by using a full-vector finite element method. It is confirmed from computed results that one of the main causes of transmission losses in air-guiding PBGFs is the confinement loss and that, even if using large air holes of diameter to pitch ratio of 0.9, at least twenty rings of air hole arrays are required in the cladding region to reduce the confinement loss to a level of 0.01 dB/km.     

Extending transmission bandwidth of air-core photonic bandgap fibers

Air-core photonic bandgap fibers offer many unique properties and are critical to many emerging applications. A notable property is the high nonlinear threshold which provides a foundation for applications at high peak powers. The strong interaction of light and air is also essential for a number of emerging applications, especially those based on nonlinear interactions and spectroscopy. For many of those applications, much wider transmission bandwidths are desired to accommodate a wider tuning range or the large number of optical wavelengths involved. Presently, air-core photonic bandgap fibers have a cladding of hexagonal lattice. The densely packed geometry of hexagonal stacking does not allow large nodes in the cladding, which would provide a further increase of photonic bandgaps. On the other hand, a photonic cladding with a square lattice can potentially provide much larger nodes and consequently wider bandgap. In this work, the potentials of much wider bandgap with square lattice cladding is theoretically studied and experimentally demonstrated.     

Amplification properties of erbium-doped solid-core photonic bandgap fibers

A novel erbium-doped photonic bandgap fiber (PBGF) with honeycomb cladding and down-doped solid-core is proposed in this letter. This fiber is more practicable than reported erbium-doped air-core PBGF due to its Gaussian-like field distribution and low confinement loss. Theoretical analysis shows that it can largely improve pump efficiency (gain-to-pump-power ratio) for small pump power and reduce the optimum fiber length by 20%-50% for a wide range of pump powers, compared with erbium-doped step-index fiber.     

Guided properties and applications of photonic bandgap fibers

The authors have reviewed some of their recent studies on photonic bandgap fibers (PBGFs). PBGFs that confine light in the core by the photonic bandgap effect of cladding have potential applications in various photonic devices. In this paper, the guided properties and tuned mechanics of anti-resonant PBGFs are theoretically illustrated. The special coupling properties in multi-core PBGFs, such as decoupling and resonant coupling effect,are then introduced. Finally, fiber Bragg grating inscribed in all-solid PBGFs is theoretically and experimentally studied, and special resonant characteristics are also observed.     

Air-guiding photonic bandgap fibers: spectral properties, macrobending loss, and practical handling

For development of hollow-core transmission fibers, the realizable fibers lengths, bandwidth, characterization, and compatibility with standard technology are important issues. We report record-length air-guiding fiber, spectral properties, splicing, and optical time domain reflectometer (OTDR) measurements. Furthermore, spectral macrobending loss measurements for two different designs of air-core photonic bandgap fibers are presented. While bending loss is observed, it does not limit operation for all practical bending diameters (>5 mm).     

Low confinement loss hybrid-guiding tellurite photonic bandgap fiber

A hybrid-guiding tellurite (TZNLP) photonic bandgap fiber (PBGF) with low confinement loss is presented in this paper. A detailed comparison between the hybrid-guiding tellurite PBGF in which the high-index rods (TLWMN) replace one row of air holes in the radial direction and the all-solid tellurite PBGF has been accomplished. Low confinement loss windows can be achieved in this novel fiber due to the collaborated action of two guiding mechanisms–total internal reflection and antiresonant reflection.     

大纤芯红外带隙型光子晶体光纤研究

针对一般红外光纤存在材料损耗高、制备工艺复杂、传输性能和输出光束质量差等问题,提出了一种适合CO2(二氧化碳)激光传输的新型大纤芯红外PBG-PCF(光子带隙型光子晶体光纤),该光纤由三角形结构光子晶体在中心抽掉19根毛细管空气孔形成大纤芯。利用PWM(平面波展开法)分析得到了传输波长为10.6μm的CO2激光的光纤带隙图;再利用基于全矢量有限元法的仿真软件COMSOL Multiphysics分析其损耗特性。结果表明,这种结构的PBG-PCF与现有的红外光纤相比,传输10.6μm CO2激光时的损耗更小,约为0.08dB/km,可满足医用传输大功率CO2激光的需要。