光纤光栅传感器的波长解调技术研究进展

光纤布喇格光栅(Fiber Bragg grating,简称光纤光栅:FBG)波长的解调是光纤光栅传感器应用的关键技术之一.在简单介绍光纤光栅传感原理的基础上,综述了近年来国内外多种光纤光栅波长解调系统的工作原理,分析了相应解调方法的优缺点,讨论了当前光纤光栅波长解调存在的技术难点,展望了其未来的研究方向.     

基于F-P滤波器的FBG解调系统改进及其寻峰算法对比分析

光纤布拉格光栅(FBG)传感器是一种新型传感器,有着非常广泛的应用前景,FBG传感信号解调是FBG传感器应用的关键技术之一。为提高可调谐F-P滤波器的解调精度,引入波长标准具加以改进,最后对几种寻峰算法进行误差比较,证明基于正交多项式最小二乘拟合法更适用于大容量分布式FBG传感网络的波长检测。     

简支梁调谐光纤光栅波长的改进算法

对使用简支梁调谐光纤光栅(FBG)波长的计算方法进行了分析,改进了传统计算公式,给出了计算光栅波长调谐量的解析式.与传统算法相比,改进算法可以直接通过梁的长度变化量计算得到波长调谐量,因此应用更加简便,可以更为直接地指导调谐实验.     

光纤布拉格光栅传感器的温度补偿研究

应力和温度变化引起光纤布拉格光栅(FBG)传感器中心波长漂移的交叉敏感效应制约了光纤布拉格光栅传感器的实用化。在简介光纤布拉格光栅传感器工作原理的基础上,综述了近年来国内外在该领域实现温度补偿的相关技术和消除或减弱传感器温度敏感的方法,阐述了光纤布拉格光栅传感器温度补偿的原理,并分析了每种方法的特点,探讨了光纤布拉格光栅传感器应用中存在的问题。     

光纤光栅传感器检测技术

阐述了光纤光栅传感器的波长移动检测技术的发展现状,分析各种检测技术的原理和性能,并对增益光纤在FBG传感网络有源检测中的应用进行探讨。     

少模光纤布喇格光栅的光谱特性研究

相较于传统的单模光纤布喇格光栅(FBG)传感器,少模FBG传感器在测量时不易受到外界无关参量的影响,精度更高,但其在光栅参数设计上缺乏相应的理论依据。针对此问题,基于FBG耦合模理论,利用OptiGrating和Matlab软件模拟分析了纤芯中存在LP₀₁模、LP₁₁模的少模FBG的反射谱。仿真结果表明:区别于传统单模FBG的单峰结构,少模FBG的反射谱具有三峰结构,光栅周期、光栅长度和折射率调制深度的变化会对各波峰的反射率及中心波长产生规律性的影响。     

基于光纤光栅级联调谐技术的波长检测系统

报道了一种检测光纤光栅传感器波长的新方案。实验系统采用新型的级联结构对电热调谐的光纤光栅滤波器进行复用,扫描分析传感信号光的峰值波长,同时用参考波长校准方法消除了电热调谐中的蠕动误差。结果表明,系统的检测范围可达23nm,波长分辨率为3.1pm,应变测量分辨率为2.56με。     

基于F-P腔滤波器的FBG温度传感器解调技术

近些年来,光纤光栅传感器成了传感领域的研究热点.对高精度的波长编码信号解调是实现光纤光栅传感的关键技术.介绍了光纤布拉格光栅(FBG)传感器的工作原理,同时对F-P腔滤波器的工作原理进行了分析,阐述了光纤光栅传感器解调技术的发展趋势,并提出了光纤光栅传感器解调技术需要解决的技术问题.     

商用仪器化的FBG传感器检测系统

综述光纤布喇格光栅(FBG)传感器的工作原理、波长解调技术、应变和温度同时测量的问题.经过十多年发展,光纤光栅传感器已广泛应用于各种领域.通过具体分析国外某公司光纤光栅传感器检测系统的产品性能指标,表明光纤光栅传感器业已解决了本身的许多技术关键和实际工程中的使用问题,进入商用仪器化实用阶段,市场前景看好.我国光纤光栅传感器处于试验性试用阶段,和国外有较大差距,我们应引起足够重视.     

基于SoC的光纤光栅温度传感器

波长漂移量的精确检测是光纤光栅(FBG)传感器的关键技术.设计了基于芯片系统(SoC)的FBG温度传感器,通过控制激光器工作波长,跟踪锁定FBG反射波长,实现温度传感解调,具有信噪比高、可靠性好、成本低、硬件简单、软件灵活并具有智能化等优点,有良好的应用发展前景.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its