Spatiotemporal and Thermal Analysis of VCSEL for Short-range Gigabit Optical Links

High-speed Optoelectronic Modules using Vertical Cavity Surface Emitting Lasers (VCSEL) coupled to Multi Mode Fibers (MMF) are a performing and low-cost solution for 10 Gigabit Ethernet (10 GbE) in short-distance optical links. A complete model of the spatiotemporal behavior of multimode VCSELs, through static and dynamic response, noise, thermal effects, and its coupling to MMF has been investigated. Relative Intensity Noise shows modal dependence and can be affected by spatial filtering due to coupling and fiber propagation. Simulations permit to evaluate critical parameters, such as modulation formats, launching conditions, and operating temperature for global bandwidth and eye diagram optimization up to 10 Gb/s. Simulation results are compared to measurements on prototype optoelectronic modules.     

Study of fiber optic sugar sensor

Over the last two decades, the fiber optic technology has passed through many analytical stages. Some commercially available fiber optic sensors, though in a small way, are being used for automation in mechanical and industrial environments. They are also used for instrumentation and controls. In the present work, an intensity-modulated intrinsic fiber optic sugar sensor is presented. This type of sensor, with slight modification, can be used for on-line determination of the concentration of sugar content in sugarcane juice in sugar industry. In the present set-up, a plastic fiber made of polymethylmethacrylate is used. A portion of the cladding (1 cm, 2 cm, 3 cm) at the mid-point along the length of the fiber is removed. This portion is immersed in sugar solution of known concentration and refractive index. At one end of the fiber an 850 nm source is used and at the other end a power meter is connected. By varying the concentration of sugar solution, the output power is noted. These studies are made due to the change in refractive index of the fluid. The device was found to be very sensitive which is free from EMI and shock hazards, stable and repeatable and they can be remotely interfaced with a computer to give on-line measurements and thus become useful for application in sugar industries.     

Fiber Optical Bragg Grating Refractometer

We have demonstrated an evanescent field refractive indexfiber sensor comprising a 42-mm Bragg grating in an etched fiber together with a tunable Distributed Bragg Reflector (DBR) laser. Characterization of different aqueous sucrose solutions resulted in a resolution of roughly 10 mM sucrose. The sensor in the presented form has a theoretical sensitivity of higher than 10 5 refractive index unit (riu) in a refractive index region close to the cladding index of the fiber. However, the technique allows for an even higher sensitivity than 10 6 riu with a proper signal processing scheme.     

800nm激光泵浦掺Nd^3＋的氟化物玻璃光纤正向双程超荧光分析

从实验上探讨了掺Ｎｄ＾３＋的氟化物玻璃光纤正向双程超荧光基本特性，包括输入－输出特性、输出－带宽特性以及输出－波长（激发）特性。并给出了理论上的拟合公式，实验表明利用氟化物玻璃光纤有望获得性能优异的有应用前景的低相干度集成化光源。     

气密性碳涂覆光纤筛选强度与电阻关系研究

通过实验分析确立了把光纤电阻作为衡量气密性碳涂覆光纤通过２％应变筛选的过渡标准。要拉制２％应变筛选的碳涂覆光纤，其电阻值应小于３０ｋΩ／ｃｍ。     

线圈型全光纤偏振器的研究

本文采用等效电流法对线圈型全光纤偏振器进行了分析计算.对应于保偏光纤中两正交传输基模的消光比,提出了一种分析保偏光纤弯曲损耗的新方法,这种方法基于将保偏光纤两个不同偏振模式分别等效为两个普通圆光纤的基模,等效参数通过测量不同偏振模式的模场半径来确定.实验证明这种理论计算方法与实验结果一致.最终,我们研制出的线圈型光纤偏振器在1.31μm工作波长下,实测消光比达30dB以上,工作偏振模式插入损耗≤3dB.     

聚丙烯胺肟螯合纤维的合成及其对铜（Ⅱ）离子的吸附

利用预辐照接枝法合成了聚丙烯胺肟螯合纤维，研究了影响接枝率，胺肟基团含量及离子吸附的因素，该纤维对铜的离子的吸附容量达０．６７ｍｍｏｌ／ｇ干纤维。     

毛细管电泳安培检测扑热息痛及其水解物

研究了各种电化学预处理条件下碳纤维电极对扑热息痛及水解物的电化学行为。确定该体系最佳预处理条件为０．２Ｖ电位下阳极化１ｍｉｎ，再于－２．０Ｖ下阴极化１０ｓ。预处理后的碳纤维伏安响应得到明显提高。运用最佳条件并在支持电解中加入添加剂后，扑热息痛及其水解物在毛细管电泳上获得很好的分离和检测。其中扑热息痛的检测下限为２．７８ｐｇ；对氨基酚为１．８４ｐｇ。     

聚丙烯中空纤维膜的微孔结构的控制

通过熔纺／冷拉伸法制备了微孔聚丙烯中空纤维膜。研究了工艺条件对微孔聚丙烯中空纤维膜的微孔结构与性能的影响。结果表明：随着纺丝温度的下降或熔体拉伸比的提高，最大可几孔径及孔隙率增大；熔纺中冷却风速提高，最大可几孔径及孔隙率较大；温度低于110℃时，热处理对最大可几孔径及孔隙率的影响较小，在120－130℃时，随着热处理温度的增加，最大孔径及孔隙率有明显增加的趋势；随着初纺中空纤维拉伸倍数的增加，孔隙率先增加而后下降。     

Synthesis of polypiperazine-amide thin-film membrane on PPESK hollow fiber UF membrane

A new interfacial polymerization (IP) procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber ultrafiltration (UF) membrane.A hollow fiber composite membrane with good performance was prepared and studied by FT-IR and scanning electron microscopy.