一种高性能环形可调谐光纤光栅激光器研究

研制了一种新型的高性能环形可调谐光纤光栅激光器。该激光器使用980nm LD作为泵浦源,使用长度为10. 8m的新型增益平坦掺铒光纤作为增益介质,采用可调谐光纤光栅滤波器进行波长调谐,调谐范围可达41nm (1528nm～1569nm) ,中心波长可精确调谐到C波段指定的ITU - T标准中心波长处, 3dB 带宽< 0. 08nm, 25dB带宽< 0. 2nm,波长稳定性优于0. 01nm,边模抑制比> 60dB。最大输出功率46. 94mW,功率稳定性优于±0. 02dB,阈值泵浦功率7. 3mW,斜率效率为39. 75%。并分析了不同腔长、不同输出耦合比对输出功率的影响。     

高信噪比可调谐环形掺铒光纤激光器的研究

报道用 980nm半导体激光器泵浦的仅用 3m高掺铒光纤连续可调谐环形光纤激光器的一些实验研究结果。可调谐谱宽可达 3 0nm(从 1.5 3 μm到 1.5 6μm) ,2 5dB带宽 <0 .4nm ,边模抑制比 >5 5dB。最大输出光功率 3 3mW ,功率稳定性优于± 0 .0 2dB。阈值泵浦功率 8.6mW ,斜率效率达 3 6.67%。     

基于M-Z滤波的波长可调谐掺铒光纤随机激光器

提出了一种基于M-Z结构的可调谐掺铒光纤随机激光器,并对随机激光输出过程、随机激光的波长可调谐输出以及随机激光的稳定性进行了实验研究。通过采用光纤熔接手段将两个2×2光纤耦合器进行熔接,构成全光纤M-Z滤波结构。实验结果表明,激光器的阈值功率为120mW,调整可调谐衰减器改变增益损耗,实现波长可调谐输出,其中单波长输出分别为1554.4,1555.2和1556.3nm,信噪比达到31.65dB;双波长输出分别为1525.9,1556.2和1531.6,1556.2nm,信噪比优于21.92dB;三波长输出分别为1527.4,1546.9,1551.6和1526.9,1530.0,1549.8nm,信噪比优于20.10dB;四波长输出为1525.9,1530.1,1547.9和1552.3nm,信噪比优于18.95dB;其中单波长和双波长的功率波动分别优于1.65和1.99dB;激光器斜率效率为0.627%。     

波长可调谐掺铒光纤激光器的特性研究

利用我们已经研制成功的不依赖于偏振的声光可调谐滤波器(AOTF)作为调谐元件,提出一种新型的线性腔的波长可调谐掺铒光纤激光器.这种激光器的结构简单,调谐范围可达60nm,而且调谐速度快,调谐非常方便. 从三能级速率方程出发,结合线性腔的激光器理论及调谐器件AOTF的滤波原理,从理论上对这种激光器的输出特性进行了分析,得到输出功率、抽运阈值功率和斜率效率随波长变化的解析式.计算了满足位相匹配条件的中心波长分别为1533 nm,1553 nm及1570 nm时激光器输出功率随波长的变化.当抽运功率为40 mW时,输出功率约为6.7 mW,抽运阈值功率为4.3 mW,3 dB线宽约0.7 nm,而且不同中心波长的激光输出稳定.通过调节抽运功率、降低损耗以及改善滤波器性能等方式,可以将3 dB线宽减少至0.4 nm.(OD5)     

基于角度调谐F-P干涉仪的C波段可调谐激光器的研究

研究了基于法布里一珀罗(F-P)干涉原理的角度调谐的滤波器特性,使用自制的滤波器进行可调谐掺Er^3 光纤激光器实验。当980nm泵浦功率为30mW时获得了稳定的单纵模激光输出,输出功率约。0.65mW,线宽低于0.1m,在35．76nm波长调谐范围内功率变化不超过1dB,边模抑制比(SMSR)大于35dB;泵浦功率为46mW时获得了最大的输出功率,约为1mW。     

调制光栅Y分支型激光器高效调谐特性研究

针对调制光栅Y分支型（MG-Y）激光器在实际应用中波长-电流查找表（LUT）构建效率低、调谐方式复杂、波长调谐时功率漂移量大等问题,对其调谐特性进行了深入研究。利用左、右反射器电流的调谐特性,设计出一种具有普适性的波长测试框架,能够高效且准确地定位激光器的平滑波长调谐路径。同时提出一种自适应功率校准算法,提升了激光器在波长调谐时的功率稳定性。测试结果表明：基于波长测试框架的LUT仅包含3147个反射器电流-波长组合;激光器的波长调谐范围为1528～1568 nm,波长调谐步长为5 pm;边模抑制比（SMSR）大于40 dB;波长准确度优于±2.9 pm;波长重复性优于1.9 pm;波长调谐时功率漂移量小于0.408 mW,稳定度为3.57%;解调出光纤非本征法布里-珀罗干涉型（EFPI）传感器的腔长变化量小于7.58 nm,可以应用于光纤传感等实际场景。     

温控FBG式4通道波长可调准OADM研究

实现了一种带温度控制的基于FBG的4通道波长可调准光分插复用器(OADMs)。对用悬臂粱法调谐的FBG中心波长温度稳定性进行了研究,设计了一种灵巧的温度控制装置,解决了FBG中心波长可调谐和温度稳定性间的矛盾。测试结果表明,实现的OADMs在环境温度范围-20℃～ 60℃,中心波长变化小于0．004nm／℃,与未经温度补偿的悬臂梁调谐光栅相比温度稳定性提高了6．75倍。利用悬臂梁方法实现了FBC;中心波长的微调,调谐范围为1nm。4路OADMs的信道间隔为0．8m,上下路3dB通道带宽小于0．3nm,符合ITU-TG．692的要求。利用自制的FBG实现OADMs的邻道隔离度大于35dB。     

基于Mach-Zehnder滤波的可调谐光纤激光器

() ()基金项目: 。摘要:为了实现高稳定性的可调谐激光输出,提出并设计了一种基于Mach-Zehnder(M-Z)滤波结构,结合Fabry-Perot(F-P)滤波器的可调谐掺铒光纤激光器,并对激光器的原理及实现方案进行理论分析和实验验证。所设计激光器系统的泵浦源工作波长为976 nm;长度5 m的掺铒光纤作为增益介质;采用全光纤M-Z结构进行滤波,并结合F-P滤波器实现单波长激光可调谐输出。实验中,通过调节F-P滤波器,在泵浦功率为60 mW时,实现了1547～1568 nm范围内单波长激光的稳定可调谐输出,波长调谐间隔小于1.7 nm,每个输出波长的边模抑制比均大于55 dB,线宽均小于0.1 nm。     

波长及功率双项可调谐的全光纤激光器

设计一种以光纤光栅和光纤环形镜作为线性谐振腔端镜的可调谐全光纤激光器,分别利用光栅调谐技术及偏振控制器实现了该激光器波长及功率的双项调节.实验得到该全光纤激光装置的最大输出功率为6.86mW,斜率效率为0.09,3dB线宽小于0.03nm.     

基于F-P干涉技术的通信波段可调谐激光器

根据F-P干涉原理设计制作了楔型F-P滤波器,使用这种滤波器进行可调谐掺铒光纤激光器实验,980nmLD泵浦功率为25mW时获得了稳定的单纵模激光输出,输出功率约0．6mW,线宽低于0．06nm,在34．2nm波长调谐范围内功率变化不超过0．5dB,边模抑制比大于35dB。     

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.     

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.     

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.     

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.     

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.     

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.     

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