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。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.