对称半导体光放大器马赫—曾德尔干涉仪解复用器的开关特性分析

分析以以半导体光放大器（SOA）为基础的对称马赫－曾德尔干涉仪（MZI）解复用器在控制脉冲和信号脉冲反向传播（CPMZ）与同向传播（TPMZ）两种工作模式下的开关特性。研究表明：控制脉冲宽度、半导体光放大器的长度和非线性增益压缩影响着控制脉冲和信号脉冲反向传播开关窗口的大小，是限制控制脉冲和信号脉冲反向传播高速工作的主要因素。当控制脉冲宽度小于半导体光放大器的渡越时间时，如时延量小于于两位的半导体光放大器渡越时间，控制脉冲和信号脉冲以向传播的峰值开关比开始恶化；当控制脉冲宽度超过半导体光放大器的渡越时间时，即使时延量大于两倍的半导体光放大器滤越时间，峰值开关比也出现恶化。因此当控制脉冲和信号脉冲反向传播高速工作时，控制脉冲应尽可能窄，且时延量必须大于两倍的半导体光放大器渡越时间以确保有较高的峰值开关比，而半导体光放大器长度效应对控制脉冲和信号脉冲同向传播的影响甚微。     

玻璃波导光功分器的研制

本文报道了Na^ —Tl^ 离子交换的K9玻璃衬底光功分器（工作波长为1.55μm），分析设计和器件的制作，并对制作的器件进行了模式损耗测试。结果表明，器件达到了预定的要求。     

顶部籽晶法生长磁光晶体硼酸铁

本文首次采用顶部籽晶泡生法在敞开体系中生长了出了磁光晶体硼酸铁单晶。选用Ｂ２Ｏ３作自助溶剂，ＬｉＦ作稀释剂，确定了原料配方。对长出的晶体作了初步的物化性能测试。讨论了晶体生长的结果。     

High-Density Read-Only Memory Disc with Ag11In12Sb51Te26 Super-Resolution Mask Layer

A novel read-only memory (ROM) disc with an Ag11ln12Sb51Te26 super-resolution mask layer is proposed and investigated for the first time to our knowledge. The carrier-to-noise ratio of more than 40 dB could be obtained from small pits (380nm), which are below the readout resolution limit (400nm), in our dynamic setup with a wavelength of 632.8 nm and numerical aperture of 0.40. Dependences of carrier-to-noise ratio on readout power,readout velocity and film thickness are studied. The results show that the optimum film thickness is 20-50nm and the corresponding carrier-to-noise ratio is more than 40dB at readout power of 4mW and readout velocity of 2m/s in our experiment. The super-resolution readout mechanism for this ROM disc is also discussed.     

增透膜的原理及常见问题的解答

增透膜也称减反膜，即能够减少反射光，增加透射光的薄膜．笔者在此简单分析一下光学镜头中所用的增透膜．     

Fast Optical Switching Using Oriented Cyanine Dye-Doped Nematic Liquid Crystal

A cyanine dye, 2-[7-（1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene）-1,3,5-heptatrienyl]-1,3,3-trimethyl-3H-indolium iodide （NK-125）, is doped in 4-cyano-4＇-pentylbiphenyl （5 CB）, and the mixture is sandwiched between two pieces of rubbed glass plates. The third-order nonlinear optical properties of the oriented NK-125-SCB layers are measured by the resonant femtosecond degenerate four-wave mixing （DFWM） technique at 760 nm. The third-order nonlinear optical susceptibility of one of the present samples is 5.5×10^-8 esu. The slow DFWM response of the NK-125-SCB layers due to a population grating is accelerated by the increasing laser power because of amplified spontaneous emission （ASE）. On the other hand, we do not observe a similar phenomenon for NK-125- polyethylene glycol （PEG-400）. Oriented NK-125 molecules in nematic liquid crystals must have very high ASE efficiency. Hence the population grating in a DFWM signal disappears within about 4 ps. It is expected that NK-125-SCB can be used as a material for very fast all-optical switching.     

用等离子体治疗牙病

等离子体清洗经常使用在材料处理和半导体工业上，虽然等离子体也可以快速地消灭细菌，但由于它们都处于高温状态，所以一直无法应用到生物医学领域．三年前，荷兰Eindhoven大学的一些物理学家发展了一种可在室温下工作的“等离子体针”。     

A Novel Analytical Approach for Multi-Layer Diaphragm-Based Optical Microelectromechanical-System Pressure Sensors

An optical microelectromechanical-system （MEMS） pressure sensor based on multi-layer circular diaphragm is described and analysed by using the proposed novel analytical approach and the traditional transfer matrix method. The analytical expressions of the deflection of multi-layer diaphragm and absolute optical reflectance are derived respectively. The influence of residual stress on the deflection of diaphragm is also analysed. Simulation results given by the finite element method are consistent with the ones which are analysed by using the analytical approach. The analytical approach will be helpful to design and fabricate the optical MEMS pressure sensors with multi-layer diaphragm based on Fabry-Perot interferometry.     

关于由衍射片的背面反射光形成的衍射图样的讨论

在光的衍射实验中,我们看到的一般是由通过衍射片的直射光形成的衍射图样,但在衍射片的另一面,同样存在着另一个衍射图样,它是由衍射片的背面反射光形成的,两个衍射图样关于衍射片对称.本文给出了这种实验现象,并用巴比涅原理解释了这种现象.