一种基于光纤光栅传输色散特性的可调谐色散补偿方案

分析了光纤光栅在禁带附近的光特性,提出了一种基于光纤光栅传输色散特性和应用变特性的新的色散补偿方案－级联光纤光栅可调谐色散补偿;从理论和实验两方面分析了它的色散补偿的可调谐性,并进行了数值模拟;讨论了这种方案在光纤通信方面特别在密集波分复用系统中的应用前景。     

光纤光栅动态色散补偿技术的研究

本文在研究了啁啾光纤光栅的可调谐特性基础上,利用啁啾光纤光栅的应变调谐特性,通过固定在同一悬臂梁的均匀Bragg光栅传感器,实现了闭环自动控制色散补偿量,研制出了一种新型的光纤光栅动态色散补偿系统,并将研制的动态色散补偿系统成功地应用于光传输系统,获得了很好的结果.     

基于长周期光纤光栅的可调谐光滤波器设计

分析了长周期光纤光栅(LPFGs)透射谱受外界环境折射率变化影响的特性及其原理,进而提出了一种新型的可调谐光滤波器的设计思路．并运用分段光栅的矩阵分析法对其进行了具体的计算。此种光滤波器具有滤波精度高、可实现滤波波长和深度单独、连续调谐及全光纤性等优点,滤波波长调谐范围可达15nm,衰耗深度调谐范围达9dB。     

Littman光栅外腔可调谐Yb3+双包层光纤激光器

本文对LD泵浦的光栅外腔可调谐双包层Yb3 光纤激光器进行了实验研究．采用Littman外腔结构，研究了Yb3 光纤激光器的调谐特性．输出激光调谐范围42nm，谱线宽度0．08nm，最大输出功率达到了460mW，斜率效率约30％．并对其输出光功率随波长的变化进行了观测和分析．     

光纤光栅传感技术及其应用

本文从光纤光栅的写入技术、光纤光栅的特性、光纤光栅的调谐技术、光纤光栅的传感原理几个方面对光纤光栅技术及其应用，尤其是Bragg光纤光栅在智能结构中的应用作了较为详细的综述与探讨，并描述了光纤光栅的发展及其现状。     

光码分多址系统可调谐编/解码器研究

介绍了光码分多址(OCDMA)系统和常用的几种编/解码器(E/D).研究了基于光纤延时线(OFDL)和基于光纤布拉格光栅(FBGs)的可调谐编/解码器,讨论了两种基于光纤延时线的可调方案,对它们的结构和性能进行了分析.讨论了基于光纤布拉格光栅(FBGs)的编/解码器,介绍了光纤布拉格光栅编/解码器的原理和利用压电陶瓷(PZT)调谐光纤布拉格光栅的参数选择.给出了一种基于光纤布拉格光栅阵列的可调谐二维编/解码器结构,并分析了它的主要优点.介绍了基于超结构光纤布拉格光栅(SSFBG)的二进制相移键控(BPSK)编/解码器和可调谐四进制相移键控(QPSK)超结构光纤布拉格光栅编/解码器的构造方法,探讨了光码分多址系统编/解码器的发展前景.     

光纤光栅外腔半导体激光器频率调谐技术研究

在分析了光纤光栅外腔半导体激光器(FBG-ECL)基本特性的基础上,调研了适用于该类型激光器的频率调谐方法,包括温度调谐法和应力调谐法,选取轴向应力调谐法改变光纤光栅的布拉格中心波长,进而实现频率调谐。利用压电陶瓷(PZT)来对光纤光栅施加轴向应力,通过调整PZT驱动电压值的大小来控制光纤光栅布拉格中心波长的变化量。实验结果表明,对于波长1550 nm的光纤光栅激光器,当PZT的驱动电压增加到126 V时,可实现 0.8 nm,即100 GHz的调谐范围以及每周期2 ms的调谐速度。     

光纤光栅声光调制特性分析

高频超声波在紫外写入的光纤布拉格光栅(FBG)上传播，产生的长周期超声光栅调制光纤光栅，形成光纤超声超结构光栅。利用模式耦合理论，分析了光纤超声超结构光栅的光谱特性，得出光纤超声超结构光栅的反射谱存在多个反射峰，其反射峰的波长间隔由超声波的频率决定。因此，可以通过改变超声波的频率，调节一阶反射谱的反射波长，从而实现宽调谐范围的快速波长可调滤波器。该滤波器与通常的声光可调滤波器相比，带宽更窄，调谐速度更快。     

光纤光栅透射谱线的测量

在已有光纤光栅调谐技术的基础上,研究了一种由不同光谱特性的光纤光栅组成的光栅对,用于测量光纤光栅谱线结构。并给出了测试结果。     

光纤光栅调谐特性的实验研究和分析

对光纤光栅的调谐特性进行了简单的理论分析和具体的实验研究，利用徽位移器(精度0．1μm)对光纤光栅进行纵向拉伸实验，实验中采用了先进的高分辨率光谱仪(分辨率为0．004nm)进行测试，实现了高精度的机械调谐和测试。实验结果比较理想，验证了理论分析的结果，两根光纤光栅分别实现调谐范围6．320nm和5．762nm，光纤光栅每拉伸约0．117％，Bragg波长位移1nm。同时发现，调谐前后的中心Bragg波长、反射率、透射谱几乎不变。     

基于游标原理的可调谐分布反射全光纤激光器

报道了一种新型全光纤离散可调谐分布反射(DBR)光纤激光器。光纤激光器为短腔结构,其有源区采用Er-Yb共掺单模光纤,有源光纤长度为6 cm。激光器采用两组级联光纤布拉格光栅(FBG)为反射腔镜,前腔镜各级联光纤布拉格光栅的布拉格波长间隔为1 nm,后腔镜为0.8 nm,利用游标原理,通过对前腔镜级联光纤布拉格光栅进行机械调谐,使前后腔镜各反射波长分别对准,实现了四个固定波长间隔为0.8 nm的离散调谐。这种光纤激光器具有波长调节准确,调谐速度快,成本低的优点,可用于作为多波长光纤传输系统的发射光源或系统检测光源,进一步增加级联光栅的组数可实现更大调谐范围。     

Tuning and chirping fiber Bragg gratings by deep etching

We have demonstrated a new method for tuning and chirping fiber gratings. It relies on etching of a fiber down to very small cladding diameter, so that the propagating optical mode in the fiber interacts with the surrounding media. A tuning range of 4.5 nm has been demonstrated with a potential of much larger tuning range by optimization of fibers. Chirped gratings were also demonstrated with this technique. These chirped gratings are very important for use in fiber dispersion compensation and optical pulse shaping.     

基于CFG的连续TTD系统研究

提出并实验验证了一个四通道的基于啁啾光栅的连续可调光控延时系统,该系统适合于频率达10 GHz的相控阵天线的波束形成及扫描,使用一种基于啁啾光栅的延时网络和一种新型的波长等间隔增大或减小的多波长可调谐线性腔光纤激光器.光纤激光器的等波长间隔,通过相等增量的作用力挤压或拉伸激光谐振器中固定在一个有机塑料盘上成一定的角度相邻的布拉格光栅来调谐.光控延时是通过被调制光在一个线性啁啾光栅的不同位置反射而实现,波长等间隔激光可获得等间隔的延时.     

Tunable optical filters for dense WDM networks

WDM is currently taking over as the leading technology in point-to-point transmission links. For optical implementation of WDM networks, logical functionalities such as wavelength (channel) selection should be carried out in the wavelength domain; thus, the development of dynamic optical devices is required. One key device is a tunable optical filter. Important features of such a filter include low insertion loss, narrow bandwidth, high sidelobe suppression, large dynamic range, fast tuning speed, a simple control mechanism, small size, and cost effectiveness. Here, an extensive overview of the different technologies used to produce tunable optical filters is presented. Among them, fiber filters such as fiber Bragg gratings and fiber Fabry Perot are the most commercialized, yet inherently limited in their dynamic speeds. For high demanding dynamics, micro-machined and acousto-optic filters can offer a good solution for microsecond tuning speeds. Faster tunable devices, in nanosecond tuning speeds, might emerge out of microresonators, electrooptic filters, and active DBR filters     

光纤光栅和环行器构成的多路光分插复用器

讨论由光纤光栅和光环行器构成的光分插复用器的结构,性能和特点,提出采用一段刻有多个光纤布拉格光栅的光纤,两个光环行器,WDM复用器和解复用器等器件,构造能够对WDM的多个信道实施分插操作的光分插复用器,该光分插复用器的插入损耗要比简单地把多个单路的光分插复用器进行级联时小得多,波分复用全光网络中的光分插复用技术,是实现波分复用网络的关键技术之一。     

Simple Reconfigurable Photonic Microwave Filter Using an Arrayed Waveguide Grating and Fiber Bragg Gratings

We demonstrate a photonic microwave finite impulse response filter with reconfiguration and tuning capabilities. The filter is based on spectral slicing of a broadband source and optical fiber as a wideband dispersive medium. An arrayed waveguide grating and fiber Bragg gratings are used to select and vary the weight of the optical taps to achieve reconfiguration and tuning     

皮秒脉冲在级联光纤光栅中的传输特性研究

基于波分复用(WDM)系统中级联光纤光栅色散特性,研究了皮秒脉冲宽度以及光纤光栅长度和耦合系数等参数对脉冲压缩的影响;以高斯脉冲为例,运用等效色散的方法数值模拟了皮秒脉冲经过常规光纤和级联光纤光栅的演化过程.结果表明,选择合适的参数,级联光纤光栅可以对在普通光纤中色散展宽的脉冲进行色散补偿.还发现,进一步增加光栅长度,可使脉冲得到有效压缩.     

Self-compensated dispersion tuning of a mode-locked fiber laserusing a linearly chirped fiber grating

A new approach of self-compensated dispersion tuning is developed to generate wavelength-tunable pulses from a fiber laser. A linearly chirped fiber grating is used in conjunction with a pair of optical circulators and modulators in the cavity. The wavelength has been electrically tuned while maintaining a constant operating frequency of 1 GHz. The laser exhibits a linear tuning relation with respect to the delay time between the electrical control signals. Three chirped gratings providing dispersions of 1446, 50, and 10 ps/nm are used respectively in the experiment and the results are compared. The highest tuning range is about 1 nm and is limited by the chirped bandwidth of the gratings     

Cladding-mode resonances in hybrid polymer-silica microstructuredoptical fiber gratings

We examine the cladding-mode resonances of fiber gratings UV written into the core of a novel microstructured fiber whose air regions are subsequently infused with polymer. The cladding spectrum changes with temperature because of the strong temperature dependence of the polymer refractive index and we show that these changes can be understood qualitatively using a simple model of the polymer-silica waveguide. Our results imply wavelength and amplitude tuning regimes for long period gratings written into this fiber with tunability enhanced over conventional long period gratings because of the small effective inner cladding diameter of our fiber     

Tuning Bragg wavelength by writing gratings on prestrained fibers

Bragg gratings at a specific wavelength are made using an excimer KrF laser and a phase mask. The wavelength can be varied for fine tuning and multiplexing applications by straining the optical fiber during UV illumination. When the strain is removed, the grating formed is at a smaller wavelength than that dictated by the phase mask for the unstrained fiber. This technique was demonstrated by writing two gratings located at the same point in the optical fiber. The transmission from the first grating was used as a means for in situ absolute wavelength tuning. The second grating made with approximately 0.2% axial strain was at 1534.54 nm. Once the grating was made, the strain was removed from the fiber leaving the second grating tuned to 1532.04 nm, a wavelength shift of 2.5 nm