科技进展

山东大学采用自己研制成功的高效率激光自倍频复合功能晶体,四硼酸铝钇钕,在国际上首次获得了从1.06μm到0.53μm的激光自倍频的运转。其技术参数为:泵浦阈值能量<2mJ;0.53μm的绿光输出能量>5mJ;0.53μ对泵浦光转换效率>10％。如果激光器设计改进,泵浦方式改换,激光自倍频参数还会进一步提高。     

LD泵浦的Nd∶YAG腔内倍频激光器及其模式

用KTP晶体研制成LD泵浦的YAG腔内倍频激光器,得到0.532μm连续绿色线偏振激光输出,阈值泵浦功率为41mW,输出功率为1.4mW,斜效率为1.7％。研究了泵浦光对倍频激光横模的影响。     

LD泵浦NYAB自倍频激光器和双波长激光器的实验研究

研制出国内第一台用LD泵浦的NYAB自倍频激光器和双波长激光器。采用直接耦合方式进行端面泵浦。自倍频激光器产生0.531μm的绿色激光,基横模运转,阈值泵浦功率为14.31mW,输出功率达2.2mW,斜效率达2.1％。双波长激光器同时产生0.531μm的绿色激光和1.062μm的近红外激光,基横模运转,阈值泵涌功率力14.81mW,输出功率达9.2mW,斜效率达7％。     

镁橄榄石可调谐激光的研究

本文报道了室温下镁橄榄石可调谐激光的实验结果。采用调QNd∶YAG脉冲激光作为泵浦源,可调谐波长范围为1.167μm到1.332μm。输出能量为11.5mJ,转换效率为16％。倍频后,获得从0.584μm到0.666μm的倍频激光输出。     

LD泵浦OF耦合NYAB自倍频激光器的初步研究

研制出国内第一台LD泵浦OF耦合NYAB自倍频激光器,产生0.531μm的线偏振绿色激光。基横模运转,阈值泵浦功率为14mW,输出功率达3.6mW,斜效率达3％,偏振度大于99.8％。     

微机控制自动调谐的NYAB自倍频激光器的研究

研制出国内第一台微机控制自动调谐的LD泵浦NYAB自倍频激光器。利用计算机控制激光器输出镜作二维扫描,精度达10~(-2)度的量级。激光器产生0.531μm的线偏振绿色激光,基横模运转,阈值泵浦功率为14mW,输出功率达3.6mW,斜效率达3％,偏振度大于99.8％。     

30dB高增益掺铒光纤放大器

由于1.536μm的掺铒光纤放大器具有高增益、低噪声和偏振不敏感等特性,因而对长距离高码速及大容量光纤通信极具吸引力. 本文采用内腔式532μm倍频YAG激光为泵浦源,其声光调Q频率为5～10kH_7,输出稳态功率大于35mV,掺铒单模石英光纤长度为25m,截止波长、数值孔径、芯径和1.536μm模斑直径分别为1.318μm、0.192、6.4/μm和7.3μm。掺铒浓度大约为40ppm,在532nm和1.536μm处的损耗分别为4.9dB和5.2dB。实验所用信号源是1.536μm InGaAsP/InP激光二极管,经过20×物镜,将其输出激光耦合入光纤,耦合效率达32％。532nm泵浦激光被逆向耦合入光纤,通过25×物镜聚焦,耦合效率大于80％。     

可调谐掺钛宝石激光泵浦的NYAB准连续绿色激光的特性

本文报道了准连续Ti~(3+)宝石可调谐激光泵浦自倍频激光晶体NYAB,获得0.531μm绿色激光输出的实验结果。激光阈值很低,平均输出功率为27.6mW,总效率为22.6％。     

LD泵浦的Nd：YLF激光器及倍频激光器

研制成LD泵浦的YLF激光器得到连续1.047μm近红外激光,阈值泵浦功率是19mW,输出功率达5.2mW,斜效率为5.1%;研制成YLF-MgO:LN腔内倍频激光器,得到连续0.524μm绿色倍频光输出,阈值泵浦功率为34mW,输出功率为0.46mW,斜效率为0.5%。对Nd:YLF晶体的受激态吸收和因其产生的荧光进行了观察研究,指出其可能的应用。本文简要报导实验方法和实验结果。     

切伦科夫倍频用质子交换MgO∶LiNbO_3波导性能研究

本文研究了用质子交换(PE)法生长的MgO∶LiNbO_3波导的性能,分析了切伦科夫倍频条件并实现了由1.06μm到0.53μm的切伦科夫倍频转换(CSHG),转换效率接近1％。     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks