取样布喇格光纤光栅的谐振方程

利用傅里叶变换和耦合模理论得到了取样布拉格光纤光栅的谐振方程,确定了其多谐振峰的位置.这一方程与光栅的周期和取样周期有关,它们共同确定了各反射峰的中心波长,与取样时的占空比、光栅长度和耦合系数没有关系.将谐振方程确定的谐振峰位置和传输矩阵得到的结果进行了比较,二者是一致的.利用谐振方程可以方便地得到取样布拉格光纤光栅的反射峰间隔.本文的结论对研究、设计和制作取样布拉格光纤光栅具有参考意义.     

室温稳定多波长光纤激光器技术的研究新进展

室温稳定的多波长光纤激光器( MWFL)中最关键的技术是如何有效抑制掺杂光纤的均匀展宽效应。综述了国际上近年来提出的实现室温稳定多波长光纤激射的主要技术。介绍了近几年我们在该领域的一些创新性研究工作:提出了多种基于多谐振峰的光纤布拉格光栅(FBG) ,如多模光纤布拉格光栅、保偏光纤布拉格光栅、取样光纤布拉格光栅等的可开关多波长光纤激光器的新方法和新结构,实现了多种波长间隔小于2 nm,室温工作稳定性好、波长及波长间隔可调的可开关多波长光纤激光器;提出了基于非线性光纤环镜( NOLM)和非线性偏振旋转(NPR)效应的两种多波长掺铒光纤激光器(EDFL)实现技术,实现了室温稳定、功率谱分布平坦的宽带多波长激光输出,3 dB带宽内的波长个数可达50个,每个波长的功率波动在2 h内小于0 .1 dB。     

DWDM系统中的光滤波技术

密集波分复用光网络的不断演进带动节点器件技术飞速发展,光滤波技术作为其中的关键之一已不仅仅是原来狭义的复用/解复用器的概念,其涵盖的范畴越来越多,包括光分插复用(OADM)、光交叉连接(OXC)、增益平坦滤波(GFF)、色散补偿(DC)、泵浦合波器(PBC)、动态增益均衡器(DGE)、波长锁定器(Wave locker)等。滤波手段层出不穷,多腔介质膜滤波器(MDTFF)、阵列波导光栅(AWG)、光纤布拉格光栅(FBG)、熔融拉锥器件(FBT)、奇偶交错滤波器(Interleaver),此外还有声光可调谐滤波器(AOTF)、闪耀光栅、全息光栅、全光纤March-Zehnder干涉…     

光纤光栅耦合器在光通信中的应用

光纤光栅耦合器综合了光纤光栅良好的波长选择和光纤耦合器多端口特性的特点,是一种低插入损耗、应用简便的全光纤器件。介绍了光纤光栅的基本结构和功能,重点分析了它在插分复用、全光交换、改善EDFA的信噪比和监测EDFA增益等方面的应用。     

一种新的光纤布拉格光栅波长移位检测技术

提出了一种利用全光纤非平衡Mach Zehnder干涉仪作为边缘滤波器进行光纤布拉格光栅 (FBG)波长移位检测的方案。这种边沿滤波器具有梳状的滤波特性 ,且其两输出臂滤波特性互补。利用其一对滤波边沿 ,可以将被测光栅的波长信息转化为功率信息进行检测。在制作时 ,通过适当改变干涉臂长差可方便地调整测量范围和检测分辨率 ,具有较大的灵活性。以两种不同的比较运算的方法消除系统功率起伏对测量结果的影响 ,都得到了较好的结果。采用该检测方案进行了光纤布拉格光栅温度传感实验 ,得到了± 10 pm的波长测量精度。     

基于少模光纤布拉格光栅的模分复用系统实验研究

本文提出了一种基于少模光纤布拉格光栅(Few-mode FBG)的模分复用通信系统,阐述了基于少模光纤布拉格光栅的模分复用/解复用原理,建立了2×2的模分复用实验系统,分别利用LP01和LP11模作为独立信道,实现了1.25 Gbps和622Mbps两路伪随机序列(PRBS)的10km传输实验,给出了传输后的眼图,分析了当激光器波长为1549.228nm时,实验系统的误码特性.实验验证了基于少模光纤布拉格光栅的模分复用通信系统的可行性,为进一步实现长距离高速率的模分复用通信奠定了实验基础.     

动态可调谐光纤光栅单/双信道滤波的实现

阐明了应力引起光纤光栅布拉格波长漂移的机理；分析了应力对光纤光栅的反射谱的影响。采用施加应力的方法，实现了基于动态可调谐的光纤光栅的单／双滤波。     

光纤布拉格光栅半导体激光器的稳定性

介绍了由光纤布拉格光栅（FBGs）组成的光纤激光干涉仪中半导体激光二极管波长稳定和调谐改进的方法,发展了基于分层介质（LDM）和传输矩阵结合法进行高精度计算任意光纤光栅（切趾、啁啾等）的模拟方法。在模拟和商业可得到的光纤光栅测量基础上,设计了1种特殊的100mm长切趾型光纤布拉格光栅。我们期望FBG在改进760nm波长半导体激光器的线宽和无跳模调谐范围的应用中能提高基于这些二极管的光纤激光干涉计的分辨率。建立了基于垂直腔面发射激光器（VCSEL）的绝对光纤激光干涉仪,使用FBG进行稳定波长和控制调谐范围,并对其装置进行了介绍。     

基于全同弱反射光栅光纤的分布式传感研究

利用弱反射光栅低反射率的特性,提出了基于全同弱布拉格反射光栅的分布式光纤传感方案。采用光波长时域反射解调技术,进行定位和解调,实现高密集度的准分布式传感。从理论上分析了光纤光栅反射率、光栅单元间隔以及传输损耗等对传感系统复用容量的影响。结果表明,这种方法可以有效提高光栅传感系统的复用容量,并降低信号解调成本。实验验证了该方案的可行性,系统复用了4个反射率为6%的光纤布拉格光栅(FBG),实现了单点、多点测量,温度测量的分辨力达到0.12℃。     

光纤布拉格光栅传感器解调系统

光纤布拉格光栅传感器的核心技术在于波长解调,这也是这种器件能否实用化的关键;本文分析了光纤布拉格光栅作为传感器的独特优势,给出了光纤布拉格光栅传感的基本原理;对近几年来国内外研究工作者所用到的波长解调方法如匹配解调法、可调谐激光器法、干涉法、滤波法等做了详细的介绍,阐述了相应的系统设计方案,并对各种方法的优、缺点进行了分析和访论;叙述了光纤光栅传感器在桥梁、大坝等大型建筑结构健康检测方面应用的实例。最后访论了光纤光栅传感器在进一步实用化中需要解决的难题,并展望了光纤光栅传感器的前景。     

基于半导体光放大器和取样光纤光栅结合Sagnac环的多波长光纤激光器

Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.     

DWDM optical millimeter-wave generation for radio-over-fiber using an optical phase modulator and an optical interleaver

We have proposed and experimentally demonstrated a novel scheme to generate a dense wavelength-division multiplexing (DWDM) optical millimeter-wave source by using an optical phase modulator and an optical interleaver. The stability of the DWDM optical millimeter wave generation is largely improved because we use an optical phase modulator without a dc-bias controller and an optical interleaver is subsequently employed to suppress the optical carrier of the DWDM source, which is not as temperature sensitive as a fiber Bragg grating. Moreover, the limitation of chromatic dispersion is greatly reduced due to avoiding the generation of higher order sidebands via driving the phase modulator with optimized RF signal.     

光纤光栅滤波器在水下光通信系统中的应用

文章提出了一种基于光纤Bragg光栅(FBG)的用于水下光通信系统接收机前站的滤光方案，并采用耦合模理论分析了FBG的传输特性，数值模拟了Bragg波长为532nm、窄带、高反射率的均匀周期高斯切趾FBG。     

A grating-based OCDMA coding-decoding system incorporating anonlinear optical loop mirror for improved code recognition and noisereduction

We demonstrate an elementary grating-based optical code division multiple access (OCDMA) code generation and recognition system incorporating a nonlinear optical loop mirror (NOLM) within the receiver. We show that the NOLM can act as a nonlinear processing element capable of reducing both the pedestal associated with conventional matched filtering and the width of the associated code-recognition pulse. The pedestal rejection allows for an improved code recognition signal-to-noise ratio (SNR) relative to simple matched filtering alone, and reduced intra- and interchannel interference noise due to code overlap. The system benefits of using the NOLM are experimentally demonstrated under both single- and multiuser operation within a variety of seven- and 63-chip 160-Gchip/s code generation, recognition, and transmission experiments based on the use of bipolar superstructure fiber Bragg grating (SSFBG) coding-decoding pairs. Incorporation of the NOLM is shown to allow error-free penalty-free operation at data rates as high as 2.5 Gb/s under single-user operation, and to provide error-free performance with reduced power penalty in two-user experiments. The narrowed pulse recognition signature offers major advantages in terms of the further all-optical processing of decoded signals, such as code regeneration and recoding     

MEMS tunable SOI waveguide Bragg grating filter with 1.3 THz tuning range for C-band 100 GHz DWDM optical network

A MEMS tunable integrated waveguide Bragg grating-based filter for C-band optical dense wavelength-division multiplexing (DWDM) network is presented and analyzed in this work. Waveguide Bragg grating being a notch filter in the transmission spectrum is used to realize a tunable filter by varying the applied voltages to the fixed–fixed beam loaded with this grating. The strain across the grating is enhanced by choosing MEMS beam configuration such that the metal electrode is the bottom-most layer of the composite fixed–fixed beam. Device dimensions are chosen to achieve a narrow full width half maximum of 0.77 nm, allowing filtering of adjacent channels of 100 GHz DWDM network. A large Bragg wavelength shift of 10.4 nm (1552.52–1562.92 nm) was achieved at 45.8 V actuation providing tuning for 14 DWDM channels with inter-channel cross talk below ? 21 dB, with tuning range of 1.3 THz.

     

Optical comb filter based on spectral talbot effect in uniform fibre bragg gratings

A comb optical filter based on the spectral Talbot effect in uniform low reflecting fibre Bragg gratings is numerically and experimentally demonstrated, relaxing the need for any chirp or equivalent phase shifts between the gratings. It can be understood by the analogy between the compression and rate multiplication of phase modulated pulse trains and sampled fibre Bragg grating spectrum formation     

All-optical TDM data demultiplexing at 80 Gb/s with significant timing jitter tolerance using a fiber Bragg grating based rectangular pulse switching technology

We demonstrate the use of fiber Bragg grating based pulse-shaping technology to provide timing jitter tolerant data demultiplexing in an 80 Gb/s all-optical time division multiplexing (OTDM) system. Error-free demultiplexing operation is achieved with /spl sim/6 ps timing jitter tolerance using superstructured fiber Bragg grating based 1.7 ps soliton to 10 ps rectangular pulse conversion at the switching pulse input to a nonlinear optical loop mirror (NOLM) demultiplexer comprising highly nonlinear dispersion shifted fiber (HNLF). A 2-dB power-penalty improvement is obtained compared to demultiplexing without the pulse-shaping grating.     

All-optical enhancement of clock and clock-to-data suppressionratio of NRZ data

A scheme for all-optical enhancement of clock and clock-to-data suppression ratio of nonreturn-to-zero (NRZ) data based on self-phase modulation is proposed and demonstrated. More than 3-dB clock enhancement and 11-dB clock-to-data suppression ratio enhancement has been realized by a semiconductor optical amplifier (SOA) and fiber Bragg grating (FBG) in reflection. Clock enhancement of more than 6 dB is possible using a FBG in transmission. Using this technique, all-optical clock recovery from NRZ data has been demonstrated     

用布拉格相移光纤光栅实现光标记交换的方法

提出了用布拉格相移光纤光栅中相移来实现低功率的光标交换的新方法。设计了一个基于该方法的光标记交换实验。实验所用的布拉格光纤光栅是在通信用的标准光纤内刻写而成,通过强泵浦脉冲作用在低强度的探测信号上。光标记交换是基于交叉相位调制来完成的。     

光纤光栅Sagnac环特性及包络带通滤波器的研究

对光纤光栅Sagnac环的传输光谱进行了理论分析和实验验证 ,在此基础上提出并实现了基于非对称光纤光栅Sagnac环的包络带通结构 ,该结构可以将光栅的带阻特性转换成带通特性 ,可在光纤光栅传感领域得到应用。