脉冲泵浦掺铒光纤增益调制特性的研究

本文研究了预激光调Ｑ选模ＹＡＧ倍频激光脉冲泵浦掺饵光纤（ＥＤＦ）的荧光特性。由于存在信号光诱导的共振受激辐射，反转粒子数迅速地回复到基态，受激辐射寿命比亚稳态寿命低四个量级。基于这一效应，本文研究了调制的１．４６μｍ半导体激光器泵浦ＥＤＦ，观察到１０ｋＨｚ以上增益调制，可以用设计快速响应的有源光纤开关器件。     

分布式EDFA中受激布里渊散射效应的研究

利用含有受激布里渊散射效应（ＳＢＳ）的传输方程，研究了透明传输和最佳掺杂浓度下，受激布里渊散射效应对分布式掺铒光纤放大器（ｄ－ＥＤＦＡ）的各种特性的影响。结果表明：受激布里渊散射消耗了ｄ－ＥＤＦＡ的泵功率，恶化了系统的噪声特性，使传输系统的最佳泵浦周期减小，所需的总泵浦功率增大     

调制泵浦EDFA的增益响应与级联放大

对调制泵浦掺铒光纤放大器（ＥＤＦＡ）的增益响应与级联放大的实验研究表明，ＥＤＦＡ小信号增益对泵浦光调制的幅度和频率响应分别呈现线性与低通（＜１ｋＨｚ）特性．级联放大为高通（＞２００Ｈｚ）特性．     

双频激光泵浦掺饵光纤放大器的增益特性

从理论上研究了双频激光混合泵浦掺饵光纤放大器（ＨＥＤＦＡ）的增益特性。着重分析了ＨＥＤＦＡ的阈值和饱和行为，证明它比一般单频激光场泵浦的掺饵光纤放大器具有更高饱和增益和更低的单光阈值等优点。实验结果支持了上述结论。     

掺铒光纤放大器的原理及应用

光纤放大器是光纤传输系统的关键部件之一,它的应用对光纤通信系统产生了巨大的影响,引起了光纤通信领域中一场新的变革。目前光放大器主要有掺稀土元素光纤放大器、受激拉曼散射(ＳＲＳ)和受激布里渊散射(ＳＢＳ)光纤放大器及半导体光纤放大器三种类型。其中以1550ｎｍ的掺铒光纤放大器(ＥＤＦＡ)最为成熟。1　掺铒光纤放大器的工作原理1.1　掺铒光纤放大器的基本模型ＥＤＦＡ的基本模型如图1所示,ＥＤＦＡ的组成分光路部分和电路部分。光路部分包括掺铒光纤(ＥＤＦ)、泵浦光源、光隔离器、光合波器(ＷＤＭ)、光耦合器;电路部分包括微处理…     

带有Bragg光栅的高泵浦效率的新型EDFA结构

本文首次提出了泵浦反射型的ＥＤＦＡ结构、理论计算表明，泵浦反射型ＥＤＦＡ较之常规型ＥＤＦＡ有高的泵浦效率，高的３ｄＢ压缩饱和输出功率，低的泵浦阈值，同时由于采用光纤Ｂｒａｇｇ光栅作反射器，使这种泵浦反射型ＥＤＦＡ在工艺上容易实现。     

光纤中受激拉曼散射对“WDM＋EDFA”系统的影响

本文从理论上推导了“ＷＤＭ＋ＥＤＦＡ”系统中受激拉曼散射（ＳＲＳ）的表达形式，并分析了影响受激拉曼散射的因素，得出“ＷＤＭ＋ＥＤＦＡ”系统中拉曼散射的影响与光纤放大器的配置关系极大的结论。进而给出了几种常用配置下受激拉曼散射限制的传输距离和光纤放大器数目的上限。     

掺铒光纤放大器800nm泵浦能带的评估

掺饵光纤放大器（ＥＤＦＡ）可以采用可靠、低成本的８００ｍ波长ＡｌＧａＡｓ激光二极管激励。我们就如何解决受激态吸收（ＥＳＡ）问题的有关方法，进行了综合性实验和理论分析。受激态吸收是该波长泵浦效率的主要障碍，采用双向泵浦或基态吸收（ＧＳＡ）能带的长波长端泵浦的方法，以附加噪声的增加为代价，可以减小ＥＳＡ对增益的影响。ＧＳＡ和ＥＳＡ的横截面谱取决于玻璃基质材料。我们对不同掺铒量的玻璃测量了ＧＳＡ／ＥＳＡ     

1.48μm泵浦的EDFA理论模型的修正与数值解

本文所建立的ＥＤＦＡ的理论模型考虑了ＡＳＥ和光纤的本征衰耗，修改了速率方程和传输方程，对泵浦光功率，信号光功率沿光纤长度的分布及ＥＤＦＡ增益特性等进行了数值解，所得结果与实验结果符合较好。     

运用EDFA提高长途干线的安全性

掺铒光纤放大器（ＥＤＦＡ）是２０世纪９０年代开始在光纤传输系统中应用的新型器件，它的推广应用为光纤通信技术带来了一场革命。这里，将简单分析一下长途干线网在引入ＥＤＦＡ后，网络所发生的一些变化。 一、EDFA简介ＥＤＦＡ的放大作用是通过１ ５５０ｎｍ波长的信号与Ｅｒ离子相互作用产生的。我们知道，Ｅｒ离子有３个能级：高能态、亚稳态、基态。其中，高能态与基态之间的能量差与泵浦光子相同，亚稳太与基态之间的能量差与１ ５５０ｎｍ的光子能量相同。而且，亚稳太的Ｅｒ离子会与１ ５５０ｎｍ的光子发生相互作用，产生受激…     

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.     

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.     

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.     

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.     

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.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-