光纤布拉格光栅解调系统的光谱数据高速传送方法

针对工程应用中使用光纤布拉格光栅(fiber Bragg grating,FBG)测量炮膛温度瞬变、高频振动等信号时光谱成像法数据传输带宽高的需求,提出了一种基于直接存储器访问(direct memory access,DMA)的光谱数据高速传送方法,设计了基于Zynq的光谱数据高速传送硬件逻辑,利用光谱成像法原理搭建了FBG解调系统,实现了DMA方式的光谱数据同步传送以及FBG波长解调计算.数据传送仿真实验与FBG中心波长解调结果表明,解调系统可以将FBG光谱数据进行高速传送,数据传输带宽为320 Mbit/s,解调速率达到34 kHz,光谱数据传送具有较高的稳定性.     

高精度光纤光栅振动解调系统研究与应用

为实现工程系统中对振动信号的检测,提出了一种基于衍射光栅的光纤布拉格光栅(FBG)振动解调系统。解调系统通过色散成像原理获取传感器反射光谱,由所设计的嵌入式单元进行信号处理,并通过专用的上位机解调软件完成数据处理与分析。将系统封装为解调仪器,能实际应用于振动信号的探测。所设计的系统波长解调范围为1 525～1 570 nm,波长重复性可达±1 pm,分辨率为0.5 pm,可实现8通道复用测量,最高光谱解调速度可达10 kHz。实验结果表明,该FBG振动解调系统能够高精度测量不同频率与幅度的振动信号,最小可探测应变约为0.319με/Hz^1/2,在结构安全监测等领域具有重要的应用前景。     

基于CompactRIO的光纤布拉格光栅解调系统

波长解调技术是光纤布拉格光栅传感器实用化面临的关键技术,提出并实现了一种基于可调谐Fabry-Perot滤波器的FBG解调系统。该系统通过NICompactRIO平台控制D/A输出信号作为可调谐滤波器的扫描信号,同时对布拉格光栅的反射波峰进行采样与处理,通过标准具和参考光栅对Fabry-Perot滤波器进行标定。实验表明,该解调系统扫描带宽50nm,在50Hz扫描频率内,可以得到稳定测量信号。     

基于ARM的嵌入式光纤布拉格光栅解调系统

分析光纤光栅传感原理,阐述可调光纤F-P滤波器的工作机理和特点,并介绍了基于ARM实现光纤布拉格光栅（FBG）传感器的解调系统的硬件结构和软件设计。采用三星公司的S3044BOX对经过可调谐F-P腔解调后的波长信息进行采集,并对得到的数据进行处理。实验结果表明系统可以满足一般的工程要求。     

光纤光栅传感信号解调技术研究

针对现有解调系统不能保证驱动电压的周期完整性的不足,提出了一种基于实时参考光路和可调谐FP腔滤波器的光纤光栅波长解调系统设计方案.其中,硬件信号调理电路由二级放大电路和二阶低通滤波电路组成,具有高信噪比、低成本等特点;软件分析处理模块含有实时数据采集、处理及保存功能的高精度上位机程序,并提出了采样点补偿算法使驱动电压能够在任何情况下都以完整的周期驱动.实验结果表明:所提出的光纤光栅波长解调系统最大测量误差为34 pm,测量范围为40 nm,最大调谐速度为100 Hz,能够对光纤光栅波长信息进行实时数据采集与处理,满足工程实际需要.     

一种准分布式光纤光栅传感实验仪的设计

本文设计的实验仪采用FBG应变传感原理、准分布式技术和匹配光栅解调法,克服了现有同类仪器相对缺乏且多为单点测量的不足.本设计采用结构相同的双悬臂梁分别作为传感与解调机构,应变的模拟与测试在仪器内部即可实现.该实验仪可完成FBG准分布式实验教学,作为相关课程的教学实验设备;亦可用作解调仪对外界匹配光栅的传感量进行解调.     

可温度自动跟踪的高精度光纤光栅电流互感器

用光纤布拉格光栅(fiber Bragg grating,FBG)粘贴到超磁致伸缩材料(giant magnetostrictive material,GMM)上作为电流互感器的传感探头,用硅钢片构建磁路系统以约束并引导交变电流产生的磁力线进入传感探头,实现交变电流的传感,此传感系统具有全光纤结构和抗电磁干扰能力。由于光纤光栅是波长编码器件,该文提出一种基于分布式反馈(distributed feedback,DFB)半导体激光器的正交解调方法。该解调方法结构简单,解调精度高,能够解耦波长信息的同时剔除了温度对光纤光栅波长漂移的影响,解决了光纤光栅对温度和应变交叉敏感的问题。实验结果表明,电流互感器最小可测电流为0.33A,最大可测电流为293.25A,满量程精度可以达0.11%。应用DFB激光器解调技术的光纤电流互感器,运用激光器的波长可调谐特性,采用经典控制理论的PID算法实现了电流与温度同时测量。     

激光干涉法一次冲击加速度校准

介绍了利用激光光栅干涉技术进行冲击加速度校准的一种方法，将冲击加速度直接绝对溯源于基本量和单位（时间和长度）。对差动式光栅激光干涉冲击校准装置的原理作了介绍，特点是使用冲击激励，通过光栅的栅距、衍射级数、激光波长及激光的多普勒频移来最终确定冲击速度和加速度的瞬时值。使用了调频信号的一种数字化解调方法实现多普勒频移数据的处理，时间分辨力为一个采样间隔，具有鲁棒性好、过程收敛、结果精确等特点。应用滑动最小二乘拟合直线段的方法实现微分运算，获得了冲击速度和加速度的瞬时测量结果，并给出了实验结果。     

单片机光纤光栅传感器匹配解调系统

通过对双光纤光栅并联匹配解调原理的研究,提出了基于MSP430F1612单片机的光纤光栅传感器解调系统。利用曲线拟合的方法对压电陶瓷驱动电压与波长偏移量的数据进行拟合计算,实现光纤光栅解调的目的。本文给出了该方案软硬件设计,并对匹配解调法的发展前景进行了论述。     

基于 F-P 标准具非线性波长校准的 FBG 传感系统解调方法

针对光纤布拉格光栅(fiber Bragg grating, FBG)解调系统在变温环境下由于波长漂移引起的解调精度不足问题,提出了一种基于法布里-珀罗(Fabry-Perot, F-P)标准具非线性波长漂移校准的FBG传感系统解调方法。研究建立了引入F-P标准具的FBG解调系统,设计了基于F-P标准具非线性误差补偿的波长校准流程,搭建了FBG解调系统在航空航天实际应用环境中的模拟实验系统,并在恒温及变温环境下进行了实验测试。实验结果表明,本文所提出方法在恒温及变温环境下的传感系统解调稳定性在±0.6 pm及±1.1 pm以内,且在变温环境下传感系统解调的波长漂移量从20.3 pm减小到0.7 pm。验证了解调方法的精度和稳定性,为航空航天等领域的结构健康监测提供了参考。     

Arrayed waveguide gratings, fiber Bragg gratings, and photonic crystals: an isomorphic Fourier transform light propagation analysis

In this paper, we present a unified Fourier transform (FT) approach to the study of arrayed waveguide grating (AWG), fiber Bragg grating (FBG), and photonic crystal (PC) devices. This methodology allows the design characteristics of transverse (AWG) geometries to be mapped on to longitudinal (or distributed) FBG and PC structures, due to a comprehensive isomorphism between these important passive optical grating-based devices. The unified approach presented here, which is based upon a modified Debye-Waller approach to the analytical solution of the coupled-mode equations, allows intuitive, yet accurate appraisal of arbitrary strength coupled structures. Exploiting this isomorphism, we relate our theoretical work to a number of practical cases. For example, we describe an FBG carousel configuration (analogous to a chirped AWG cascade) offering virtually ripple-free third-order dispersion compensation of 6.61 ps/nm/sup 2/ over a 100-GHz bandwidth.     

Polymeric 16×16 arrayed-waveguide grating router usingfluorinated polyethers operating around 1550 nm

A 16×16 arrayed waveguide grating (AWG) router with a channel spacing of 0.8 nm (100 GHz) operating around the 1550-nm wavelength has been fabricated using newly synthesized fluorinated polyethers. It has a good processibility and a high thermal stability up to 510°C. The propagation loss of the buried-channel waveguide is about 0.4 dB/cm at the 1550-nm wavelength. The on-chip insertion loss ranges from 5.5 to 11 dB and the crosstalk is less than -27 dB. The AWG router shows good cyclic rotation property of the wavelength channels with an error smaller than 0.03 nm     

Recent advances in high-density and large-scale AWG multi/demultiplexers with higher index-contrast silica-based PLCs

This paper reviews recent progress on high-density and large-scale arrayed-waveguide-grating (AWG) multi/demultiplexers, which have been developed for wavelength division multiplexing (WDM)-based photonic networks. The AWG has been the key to the construction of flexible and large-capacity WDM networks. This is because, compared with conventional filters consisting of thin-film interference filters and microoptics, the AWG offers the advantages of low loss, high port counts, and mass productivity. To improve such characteristics further, low-loss, higher index-contrast (super-high /spl Delta/) planar lightwave circuits (PLCs) with a bending radius of 2 mm have recently been developed. It has been shown that these PLCs are effective for use in constructing a compact AWG module with 1/5 the volume of a conventional module and large-scale AWGs with 256 and 400 channels. Three techniques for low-loss fiber connection with spot-size converters have also been developed for the super-high /spl Delta/ PLCs, and it has been confirmed that these techniques can be applied to the fabrication of AWG modules. Furthermore, two-stage tandem AWG-type multi/demultiplexers with more than 1000 channels have been demonstrated. This paper describes the progress that has been made on these high-density and large-scale AWGs, which are expected to contribute greatly to the construction of future photonic networks including optical add/drop multiplexing systems and optical crossconnect systems.     

Optical delay line based on arrayed waveguide gratings' spectral periodicity and dispersive media for antenna beamforming applications

An optical delay line (ODL) based on the free spectral range periodicity of arrayed waveguide gratings (AWGs) and dispersive media is analyzed with emphasis on the AWG physical features that limit its performance as a photonic antenna beamforming network. This ODL presents multiple simultaneous true-time delay, straightforward multibeam capability and a drastic cost reduction in comparison with previously reported schemes. Moreover, a simulation model of the ODL that takes into account the AWG frequency misalignment is presented. Finally, experimental results are also provided for 40-GHz electrical signals.     

Tuning range extension by active mode-locking of external cavity laser including a linearly chirped fiber Bragg grating

We demonstrate electrical wavelength tuning by mode locking of an external cavity laser (ECL) with linearly chirped fiber Bragg grating (LCFBG). The configuration consists of a laser chip providing the gain coupled to an LCFBG with a large chip rate of 10 or 55 nm/cm providing the counter-reaction for laser oscillation. The laser chirp is electrically modulated by a sinusoidal signal in such a way that the ECL is mode locked. By changing the modulation frequency, a wavelength tuning range of 27 nm is achieved with the 10 nm/cm LCFBG, and a partial tuning range over 41 nm is demonstrated with the 55-nm/cm LCFBG. The output pulse stream at a specific mode-locking frequency and a corresponding wavelength is obtained for both positively and negatively chirped grating. A time bandwidth product reduction is measured in the case of negatively chirp grating when compared with positively chirp grating. A simple general law between the laser parameters is given (locking frequency, tuning range, and FBG chirp value). The parameters for a 40-nm tunable source modulated at 10 GHz are given. This simple tuning mechanism is very well adapted for a structure that requires accurate wavelength monitoring.     

基于布拉格光纤光栅测量湿蒸汽湿度的基础理论与前期试验研究

提出一种基于布拉格光纤光栅(fiber Bragg grating, FBG)传感技术测量湿蒸汽湿度的新方法。在理论推导FBG测量湿度模型的研究基础上,利用FBG涂敷湿膨胀材料的技术,把测量湿度的问题转换为FBG测量微应变的技术问题。建立悬臂梁振动频率测量装置,采用FBG精确地测出了前4阶振动频率,与加速度传感器(AT)和振动及动态信号采集分析系统(CRAS)等不同方法进行了对比试验,测量结果吻合。对FBG的粘贴位置、激励位置等也进行了试验研究。试验结果证明FBG对悬臂梁微应变(振动)测量有很高的精度和动态特性,且试验的可重复性很好,为下一步测量湿度的试验研究奠定基础。     

基于 FBG 改进泄压阀的旋叶式压缩机 排气压力感知研究

针对旋叶式压缩机排气压力精准监测难问题,提出了基于光纤布拉格光栅(fiber Bragg grating, FBG)改进泄压阀的旋叶 式压缩机排气压力感知方法。 首先,依据旋叶式压缩机泄压阀结构特点,结合 FBG 传感理论,建立了膜片式压力传感器模型, 揭示了压力与中心波长的映射关系;其次,设计了基于泄压阀的三段式 FBG 压力温度复合传感器,理论分析表明该传感器灵敏 度为 304. 26 pm/ MPa;最后通过仿真实验分析,研究了膜片半径、厚度对传感器灵敏度的影响,得到了最优半径与厚度组合(R = 5 mm, h = 0. 6 mm),实验灵敏度为 330. 78 pm/ MPa,研究对旋叶式压缩机状态监测及功耗控制具有重要的理论和实际工程 价值。