一种用于压力传感的光子晶体光纤的研究

文章提出了一种新型结构的用于压力传感的高双折射光子晶体光纤(PCF).在外界横向压力作用下,PCF两个偏振态的有效折射率发生改变,PCF的双折射随之变化,通过测量双折射改变引起的偏振态变化,可实现PCF的压力传感.仿真结果表明,高双折射PCF受到横向压力后,双折射线性变化显著,达到0.7×10<'-5>/MPa.     

高双折射太赫兹光子晶体光纤的研究进展北大核心CSCD

随着太赫兹技术的不断发展,太赫兹波导逐渐成为研究热点之一。相比于太赫兹聚合物波导,太赫兹光子晶体光纤(PCF)在高双折射方面具有明显优势。在介绍传统太赫兹波导技术研究现状的基础上,重点分析和总结了基于不同原理和不同结构的高双折射太赫兹PCF,对其优缺点进行了对比,并对高双折射太赫兹PCF的应用现状及后续的工作方向进行了总结和展望。     

高非线性高双折射光子晶体光纤特性的理论研究

基于全矢量有限元法,设计了一种新型零色散波长为1550 nm的高非线性双折射光子晶体光纤(PCF),并分析了PCF的有效折射率、有效模面积、双折射、非线性系数以及色散特性。数值结果表明,当光纤包层孔间距Λ为1.6 μm,大空气孔直径d1为1.4 μm,小空气孔直径d2为0.74 μm和0.76 μm时,光纤的零色散波长都在1550 nm处,该PCF的双折射为4.049×10-3,非线性系数可达28.4 km-1·W-1。这种高非线性高双折射PCF,在1550 nm通信波段具有非常广泛的应用前景。     

高双折射低色散光子晶体光纤设计

为了高效传输太赫兹(Terahertz,THz)波并促进太赫兹的实际应用.提出了一种具有高双折射,低色散特性的太赫兹光子晶体光纤(Photonic Crystal Fiber,PCF).利用全矢量有限元法对所提出的PCF 结构进行数值仿真,分析了结构参数与双折射以及色散的关系.仿真结果表明,该光纤在0.9～1.3 TH...     

光子晶体光纤的高模式双折射

随着干涉技术在雷达通信等领域的广泛应用.对光纤的偏振特性要求越来越高.阐述了高模式双折射的光子晶体光纤(PCF)的独特特性,讨论了其偏振特性受温度变化的影响,并与传统保偏光纤做了比较,介了高双折射光子晶体光纤的结构设计及发展现状,并展望了其应用前景.     

高双折射全内反射光子晶体光纤的特性研究

文章应用全矢量有效折射率方法(FVEIM)对芯区具有两个椭圆小空气孔的全内反射光子晶体光纤(TIR-PCF)进行了研究.结果表明,光子晶体光纤(PCF)的芯区折射率与包层区等效折射率的差随波长的增大而增大;固定包层空气孔的相对孔径,PCF基模的两个正交偏振态简并被打破,呈现出模式高双折射;随着芯区小空气孔椭圆率变大,模式双折射增大,PCF的总色散曲线变平坦.     

一种中心多孔缺陷的保偏光子晶体光纤

探索了全反射型光子晶体光纤(PCF)中空气孔的排列形状和尺寸参 数与双折射之间的关系,通过结构优化设计出一种双折射为3.4×10－3且单模工作的二孔中心缺陷实芯PCF,并采用多元非线性回归拟合的方法得到了这 种PCF双折射的数值经验方程式,为保偏型PCF的研制提供了理论依据。     

有中心缺陷孔的矩形点阵PCF双折射特性研究

采用全矢量有限元法研究了具有中心椭圆缺陷孔的矩形点阵PCF(光子晶体光纤)的双折射特性。结果发现,该新型PCF的双折射特性对波长和光纤的结构参数具有较强的依赖关系,与无中心椭圆缺陷孔的矩形点阵PCF相比,在中心缺陷孔参数bc/Λ=0.075、中心空气孔椭圆率η=2.2、包层结构参数Λ=2.0μm和d/Λ=0.48时,该新型PCF具有更高的双折射。     

高压力光子晶体光纤传感器系统的研究

光子晶体光纤(PCF)压力传感器可广泛用于各种环境压力监测中.采用全矢量有限元方法对双芯光子晶体光纤的双折射特性进行了分析,采用二阶微分方程理论模型模拟了光子品体光纤高压力传感器对外界压力的响应,并应用这个模型讨论了外界压力作用对敏感元件有效折射率和双折射的影响,提出了一种高压力光子晶体光纤传感器方案.计算结果表明高压力致双空气孔芯光子晶体光纤的双折射值可达很高,光子晶体光纤传感器系统更为简洁紧凑.     

双芯光子晶体光纤温度传感特性的研究

设计了一种双芯光子晶体光纤(PCF),并在其两个纤芯中填充混合热敏液体,采用全矢量有限元法和光纤模式耦合理论,研究了温度对填充后PCF的有效折射率、双折射、耦合长度以及限制损耗的影响。研究表明,参量对温度比较敏感,且PCF双折射达到10-3数量级。     

Ultrahigh Birefringent Photonic Crystal Fiber With Ultralow Confinement Loss

A photonic crystal fiber (PCF) with circular air holes in the fiber cladding and elliptical air holes in the fiber core is proposed. According to calculation, both ultrahigh birefringence (larger than 0.01) and ultralow confinement loss (less than 0.001dB/km) can be achieved simultaneously over a large wavelength range for a PCF with only four rings of circular air holes in the fiber cladding. The confinement loss in this PCF can be effectively reduced while the birefringence almost remains the same. The proposed design of the PCF is a solution to the tradeoff between the birefringence and the confinement loss for the originally reported highly birefringent elliptical-hole PCF. Moreover, an approach to modify the effective index of fiber core is also suggested in this letter     

Dependence of birefringence on elliptical-hole orientation in photonic crystal fibers

In this paper, the dependence of birefringence on the orientation of elliptical holes in triangular-lattice elliptical-hole photonic crystal fibers (PCFs) is investigated numerically. A resonant enhancement of birefringence between the anisotropic lattice arrangement and oriented elliptical holes is observed, and the birefringence varies periodically with the elliptical-hole orientation. When the major axes of adjacent elliptical holes are parallel, the birefringence approaches the maximum. Based on the numeric analysis, a novel highly birefringent PCF is proposed, and the maximum modal birefringence of 0.086 is achieved.     

Design of low-confinement-loss and highly birefringent index-guiding photonic crystal fibers

We present a systematic scheme to achieve both high birefringence and low confinement loss in index-guiding photonic crystal fibers （PCFs）, using a structurally-simple PCF with finite number of air holes in the cladding region. By increasing the size of the outermost-ring air holes in the cladding region, highly birefringent PCFs with low confinement loss can be successfully achieved. The design strategy is based on the fact that the modal birefringence of PCFs is dominated by the inner-ring air holes in PCF, which is verified by a full-vector finite element method with anisotropic perfectly matched layers. Numerical results show that modal birefringence in the order of 10-3 and confinement loss less than 0.1 dB/km can be easily realized in the proposed PCF with only four rings of air holes in the cladding region. We expect that such fibers will be much easier to be fabvicated than those with more air holes in the cladding region.     

A novel high birefringence equal diameter circular-hole photonic crystal fiber

A novel equal diameter circular-hole photonic crystal fiber (PCF) with high birefringence is proposed and numerically analyzed by employing the finite-element method. The proposed PCF’s birefringence is 10-3, which can reach 2 orders higher than that of traditional high birefringence fiber, and this equal diameter circular-hole structure reduces the difficulty of the actual drawing process. The effect of different parameters on the birefringence of this PCF is investigated, and the application of the Sagnac interferometer based on fiber filling technology in temperature sensing is studied. The result shows that the high birefringence PCF can be used in both optical communication and optical sensing fields.     

椭圆孔光子晶体光纤的偏振特性

摘要采用正交函数算法，提出了一种新型椭圆孔光子晶体光纤的本地正交函数模型。采用两种周期性结构的叠加构造超格子，用以表征光子晶体光纤(PCF)的横向折射率分布，同时将横向电场展开为Hermite-Gaussian函数。从电磁场的波动方程出发得到关于传播常数的本征方程。进而得到光子晶体光纤的传播常数、模场分布、偏振特性等传输特性。应用此模型讨论了椭圆孔光子晶体光纤基模两个偏振模式的双折射和群速度走离特性。研究表明，椭圆孔光子晶体光纤具有较大的模式双折射和群速度走离，双折射、群速度走离与频率的依赖关系和普通保偏光纤不同。另外椭圆孔光子晶体光纤还可实现在单模区同时保持高双折射和零群速度走离，可用于研究光纤的非线性。     

椭圆芯扁六角聚合物光子晶体光纤的偏振特性

采用全矢量定域基函数模型,以聚合物PMMA为基材,研究了椭圆芯三角点阵扁六角结构光子晶体光纤(Photonic crystal fibers,PCFs)的偏振特性,分析了其相位模双折射和群模双折射与相对孔间隔比的依赖关系,并与椭圆芯三角点阵正六角结构PCFs的研究结论进行比较;研究发现,椭圆芯扁六角结构PCF的偏振特性强烈的依赖于光纤的结构参数,由于色度色散的存在,在短波长段,群双折射远远高于相位模双折射,通过适当调节光纤的相对孔径和相对孔间隔比,有望在给定波长实现高双折射和零偏振模色散单模运行.该研究为高双折射聚合物光子晶体保偏光纤的制备提供了理论依据.     

用于光子晶体光纤研究的超格子构造法

提出应用“超格子构造法”研究光子晶体光纤(PCF)的传输特性。电场用正交完备的厄米-高斯(Hermite-Gauss)函数展开,有中心缺陷的周期性分布的介电常数用两组不同周期的介电常数分布迭加构成超格子，每组介电常数都用余弦函数展开,然后利用波动方程及厄米-高斯函数的正交性。得到光子晶体光纤的传输特性(模场分布、双折射、色散)。模式双折射的大小可用以衡量该算法的精度。     

Theoretical and experimental study of the birefringence of a photonic crystal fiber

Thanks to a magneto-optical method, we have measured the beat length of a photonic crystal fiber (PCF). Our experiments emphasize the singular behavior of the birefringence of a PCF versus the wavelength. We have also studied the birefringence of perfect photonic crystal fibers by means of the finite-element method. We show that detailed attention must be paid to the conditions of simulation for the calculation of the birefringence. Discrepancies between theoretical predictions and experimental results are pointed out and some explanations are proposed.