浅析大尺寸光纤预制棒(OVD法)的制备工艺

光纤预制棒的大型化是降低光纤拉丝成本的必要手段,本文介绍了利用OVD法生产大尺寸光纤预制棒的工艺方法,主要包括大尺寸光纤预制棒在沉积、烧结、保温过程中的设备与工艺介绍。     

浅谈大尺寸预制棒表面预处理

进入成熟期的光纤光缆行业选择大尺寸预制棒高速拉丝技术是提高生产效率、降低生产成本的主要发展方向之一.大尺寸预制棒表面预处理是大尺寸预制棒高速拉丝技术中的重要环节,其直接影响光纤的质量.本文主要探讨大尺寸预制棒表面预处理的工艺选择与设备控制,及处理效果的分析.     

光纤预制棒保温工艺的研究

通过Masao Kawach等建立的烧结终止阶段封闭球形气孔模型烧结条件介绍了光纤预制棒中氦气的产生原因。保温工序可以减少石英玻璃内的气孔以降低光纤预制棒内的He,He在石英玻璃中的扩散机理符合Fick定律,据此分析出了在微正压条件下烧结的光纤预制棒,通过保温处理后,氦气在光纤预制棒内的浓度分布符合正态分布。试验结果显示,延长保温时间,光纤预制拉丝时裸纤气泡减少;保温时间不变,光纤预制棒直径增大,拉丝时裸纤气泡增多。文章的研究成果将对不同半径光纤预制棒保温工艺的设置具有积极的指导意义。     

大尺寸预制棒高速拉丝技术研究

本文对Φ120-200mm预制棒、2000m/min高速拉丝技术进行了较为深入的研究.分别介绍了大尺寸预制棒高速拉丝对光纤衰减、翘曲度、不圆度、包层直径波动和强度方面的影响。通过对拉丝炉结构和光纤退火装置的改造,优化了拉丝炉温场和气流分布.大大改善了大尺寸预制棒高速拉丝光纤衰减、翘曲度、不圆度、包层直径波动和强度性能。     

VAD提升速度的控制方法

1.引言VAD（轴向气象沉积）工艺作为一种主流光纤预制棒制造工艺,其工艺过程是在加热的条件下,使液态原料Sicl4及Gecl4气化,经由流量计控制流量的载流气体将原料输送至喷灯,原料气体在喷灯火焰中发生水解反应,产生SiO2和GeO2氧化物颗粒,这些颗粒附着在初始种棒上,使种棒下端不断＂生长＂,最终形成预制棒松散体。为保证松散体的外形尺寸的几何精度,初始种棒会根据松散体的生长速度不断提升,同时以一定的速度旋转。     

大尺寸光棒高速拉制技术的精细化探索

随着光纤通信的飞速发展,光纤使用规模和光纤制造规模不断扩大,光纤制造技术也随之不断向大尺寸光纤预制棒使用和高速拉制技术发展。与此同时,随着光纤通信竞争的日益激烈,客户对光纤的要求越来越高,并且对光纤厂家的全面制造能力提出了更高的要求。为进一步适应市场的需求,烽火通信决定开发150mm大尺寸光纤预制棒的高速拉制技术,在提升光纤制造规模的同时,全面提升光纤的生产质量管理水平,从而提供更具竞争力、更有品质的光纤产品,以充分满足客户的需求。     

新型挤压法制备硫系玻璃光纤及其性能研究

选用组分为Ge15Sb20S65和Ge25Sb5Se70的两组硫系玻璃,制备了多种尺寸的高质量硫系玻璃,分析了两组玻璃的物理、热学和光学性能;利用复合层叠挤压法制备了硫系玻璃光纤预制棒,避免了钻孔法或其他机械加工引起的预制棒界面缺陷,且光纤端面结构可随模具尺寸自由设计,挤压后光纤预制棒结构整齐,内外界面整洁光滑;利用高温聚合物保护的预制棒具有良好的机械性能,用光纤拉丝机将具有保护层的预制棒拉制成光纤;利用普通光纤抛光机进行端面抛光,光纤端面结构均匀,界面无明显缺陷。傅里叶红外光纤光谱仪(FTIR)测试光纤损耗谱表明,在波长4.8μm处光纤的最低损耗为2.63dB/m。     

超细40μm保偏光纤预型件的测试

光纤预制棒的折射率的分布及几何尺寸决定了光纤的传输特性,因此,精确测量其折射率分布及尺寸非常必要.文章首先介绍了细光束法测试光纤预制棒折射率的原理以及PK2600的测试原理,随后对保偏光纤预型件进行了测试分析,测试结果表明保偏光纤预型件一致性良好.     

大尺寸光棒高速拉制技术的精细化探索

通过对光纤拉制工艺进行改进,将高温炉、送棒系统、冷却系统、固化系统和收丝系统进行适应性改进,并严格拉丝过程控制,烽火通信在大尺寸光棒高速拉制技术方面进行了精细化改善的有益探索,实现了长达2m,直径达150mm以上的大尺寸光纤预制棒的高质量拉制,可实现一次性稳定拉制光纤长度达到2500km的水平,有力提升了光纤的产出效率,大幅提高了光纤的产品质量。     

大预制棒可大大降低光纤生产成本

据NTT声称,双火焰VAD工艺能够大大降低光纤的生产成本,显然,该公司想把低成本光纤广泛用于用户回路。 NTT认为,降低光纤成本的关键在于可连续拉丝的大预制棒。NTT公司的实验室使用双火焰工艺生产出比标准预制棒大6倍的预制棒(相当于660km光纤),并以每分钟5克的速度拉成光纤。在VAD工艺中,四氯化硅和其它原材料被送进氢氧炉,由于其化学反应,在仔棒的顶端生成玻璃粒子,这就沉积成多孔的预制棒。然后再对该棒烧缩(加热),使之成为既均匀又透明的棒体。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.