共查询到20条相似文献，搜索用时 0 毫秒
1.
YU Qi-lei LE Zi-chun ZHU Hong-ying 《光电子快报》2006,2(4):259-262
Inthe history of the development of pupil filters,to o-vercometheli mitsinresolutioni mposed by diffractionini magingsystems has hadlong beingthe ai mof manyre-searches.The spot size(Δr)and the depth of focus(DOF)are relative to the numerical aperture(NA… 相似文献
2.
XU Yong WANG Zhi-gong GUAN Yu XU Zhi-jun QIAO Lu-feng 《光电子快报》2005,1(3):179-181
In this paper we describe a full-integrated circuit containing all building blocks of a completed PLL-based synthesizer except for low pass filter（LPF）. The frequency synthesizer is designed for a frequency hopping （FH） transceiver operating up to 1.5 GHz as a local oscillator. The architecture of Voltage Controlled Oscillator （VCO） is optimized to get better performance, and a phase noise of -111.85-dBc/Hz @ 1 MHz and a tuning range of 250 MHz are gained at a centre frequency of 1.35 GHz. A novel Dual-Modulus Prescaler（DMP） is designed to achieve a very low jitter and a lower power. The settling time of PLL is 80 μs while the reference frequency is 400 KHz.This monolithic frequency synthesizer is to integrate all main building blocks of PLL except for the low pass filter, with a maximum VCO output frequency of 1.5 GHz, and is fabricated with a 0.18 μm mixed signal CMOS process. Low power dissipation, low phase noise, large tuning range and fast settling time are gained in this design. 相似文献
3.
WEN Chuan-jing YANG Ji-sheng 《光电子快报》2005,1(1):1-4
We use Joness matrix method and the global optimal method to investigate the propagation characteristic of surface acoustic wave（SAW） for X-cut single crystal Lithium Niobate（LiNbO3 ）. As an application, a novel integrated acousto-optical filter,which allows to minimize the dimension of AO cells and suppress side-lobes,was designed on the base of LiNbO3 crystal. 相似文献
4.
FU Dong-xiang MA Jun-shan CHEN Jia-bi HOU Lin-Lin 《光电子快报》2006,2(2):151-154
Thetrendofmicroarrayishigh densityandmore spotswhoseareasaresmallandarealignedonthechips.Fluorochromeoneveryspotislittleandenergyof excitedfluorescenceislittle.Sothespotsofimageare small.Thedifferenthybridizationonthesamechiphasdifferentintensityofspots[1… 相似文献
5.
In recent years ,the demand of the project survey grewincreasingly,sothetorsionsensor has obtainedextensiveattention.But the related studies about optical fiber tor-sionsensor are veryfewinthe domestic andforeign[1-3].Inthe traditional torsion sensor we p… 相似文献
6.
ZHAO Tai-fei YU Hong-fang LI Le-min 《光电子快报》2006,2(6):445-448
Pre-configuration Cycle (p-cycle) is a promising ap-proach for protecting working capacities in WDMnet-works because of its ability to achieve ring-like recoveryspeed while maintaining the capacity efficiency of amesh-restorable network[1].The first and t… 相似文献
7.
LI Xiao-feng ZHANG Bai-lei LIN Mi QI Li-mei 《光电子快报》2005,1(3):209-212
Thereis cold-heat exchange under the large tempera-ture gradient in the space environment ,andin space-to-ground laser communication links the optical reflectorson a satellite in orbit someti mes need to be placed out-side the capsule.Therefore,tremendous thermal distor-tions will occur onthe optical mirror surface,which maybring shift andspreading ofits reflectedfocus andthere-by influences the performance of space-to-ground lasercommunicationlinks . Although there are many reports on thermal… 相似文献
8.
ZHONG Zhi-rong ZHANG Li-hua YANG Hong-qin JIANG Yun-kun 《光电子快报》2006,2(5):334-335
Optical couplers arei mportant componentsinthe sys-temof optical signal processing,optical communicationand optical calculation.Therefore many people areinter-estedinseekingfor those couplers with uniquefunction.Photonic crystals (PC)[1-2]have drawn great… 相似文献
9.
AN Jun-ming WU Yuan-da LI Jian-guang WANG Hong-jie HU Xiong-wei 《光电子快报》2006,2(4):256-258
With the rapid increase of global information capaci-ty,all optical wavelength division multiplexing(WDM)networks are very attractive because they are capable ofprocessing broadband optical signals without convertingthem to electronic signals.Large channe… 相似文献
10.
ZHOU Xiu-li HU Yu 《光电子快报》2005,1(3):232-234
A new class of multilength, constant-weight and two-dimensional multiwavelength optical orthogonal code （2D MWOOCs） with large capacity and good correlation properties is constructed based on multilength one-dimensional （1D） OOCs. The performance of these new MWOOCs in an OCDMA network with double-services is analyzed. The result shows that media with the shorter codeword performs much better than the media with longer codeword, and OCDMA system with these new multilength MWOOCs performs well. These features allow multimedia transmission of large capacity in OCDMA system. 相似文献
11.
XIE Mei-hua WANG Zheng-ming 《光电子快报》2005,1(2):144-147
In many image resolution enhancement applications, the blurring process of the imaging system is unknown. This paper discusses the problem of single image blind resolution enhancement without estimating the point spread function （PSF）. A regularization model is constructed for image enhancement based on the prior informaton of image error and image gray value,which does not need any prior in- formation of PSF. Moreover, through the solution of Euler equations, an an isotropic nonlinear diffusion equation are obtained,which can avoid the high computational cost of regularization model. Furthermore,in order to get sub-pixel superresolved image, the regularization model for image enhancement is extended to the enlargement of image, which can enlarge and enhance image at the same time. Last,to get clearer edges, a high frequency enhancement filter is used on the superresolved image. Numerical results show that the new model can get much clearer super-resolution images than traditional methods, and the peak signal to noise ratios （PSNRs） are also higher than traditional methods. 相似文献
12.
XU Ming JI Jian-hua 《光电子快报》2006,2(3):199-202
Recently,the dispersion-managed solitons(DMS) areof great interest in soliton communication systems .Be-cause of some prior advantages compared with conven-tional solitons ,such as higher pulse energy and signalnoise ratio,lower averaged dispersionline an… 相似文献
13.
WU En-qi KE Ying-lin LI Jiang-xiong 《光电子快报》2005,1(1):61-64
Small diameterpipesareusedwidelyinmanyfields, suchasenergyindustry,chemicalindustry,aviation,weaponmanufacturingandsoon.Theinspectionof thesepipesisveryimportantbecauseofthebadworking conditions.Therearemanymethodstoinspectthepipeswithinnerdiameterslargerthan20mm,suchasthe wholecircleimagemethod[1],theringopticalcutting imagemethod[2],thelaser beamscanningdisplacementmeasuringtechnique[3],theCCTVcameramethod[4], Omni directionalmethod[5]etc.Butfewmethodscande tectthepipeswithaninnerdiameter… 相似文献
14.
WEN Tao ZHUANG Zhao-wen WEI Ji-bo MA Dong-tang 《光电子快报》2006,2(1):34-36
In mobile atmosphere laser communication,the fastand accurate beamsteeringis one of the key techniquesfor acquisition,tracking and pointing(ATP) of laser sig-nals .Compared with the normal loop-locked trackingand pointing system composed of fast steering … 相似文献
15.
ZHANG Wei-gang WU Zhi-gang LIU Yan-ge YANG Yi-fei KAI Gui-yun ZHAO Qi-da YUAN Shu-zhong DONG Xiao-yi LI En-bang XI Jiang-tao Joe Chicharo 《光电子快报》2005,1(1):5-9
FiberBragggrating(FBG)isasignificanttechnology thatisusedtodesignkeydevicesorcomponentsinthesystemsoffibercommunicationandfibersensing[1], suchastunablefiberlasers[2],WDW/DM[3],WADM[4],tunablefiberfilter[5],fiberdispersioncom pensation[6],gainflattingofEDFA[7],FBG typeinter ferometer[8]andfibergratingsensors[9,10].OneofthekeyresearchissuesonFBGdevicesistomakethetun ingwavelengthdeviceswhichhavegoodcharacteristics ofwidetunablewavelengthrange,stableoutput,goodmultiplexingcapability. … 相似文献
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17.
WANG Hong-liang QIAO Xue-guang ZHOU Hong SHAO Min WEI Ting LIU Ying-gang LI Ting 《光电子快报》2005,1(2):103-106
No matter designing and manufacturing a FBG pres-sure sensor ,or monitoringthe strain on material surfaceby using FBGas a pressure sensor ,the difficult technicalproblems to be solved are as follows :first ,howto effec-tively couple and propagatethe external stresstothe ax-ial direction of FBGthrough the underlay material ;sec-ond,howto make the FBGpressure sensor achieving aneffect of enhancing sensitivity;third,how to ensure alinear relationship between FBG′s reflection wavelengthand t… 相似文献
18.
ZOU Jing ZHAO Sheng-zhi YANG Ke-jian LI Gui-qiu SONG Peng 《光电子快报》2005,1(2):113-116
Recently,some feasible ways have been put forwardsto determine the thermal focal lengthfTof gain mediumin end-pumped solid-state laser ,such as CCD-photo-graph[1]and stable cavity condition[2].However ,thismethodinvolves the complicated experi mental setup andcannot be directly applied for high power pump due tothe saturation effect of CCD.Stable cavity conditionmethodis relatively si mple,but since there is no laseroutput when the stable cavity just turns into unstablesome parts of energy o… 相似文献
19.
Supercontinuum（SC） generation in a dispersion-shifted fiber（DSF） pumped by a 10 GHz regeneratively mode-locked fiber laser（RMLFL） is presented. Optimization of pump wavelength leads to a 20 dB bandwidth of 58.73 nm,which covers the whole C band and part of L band. Using an angle-tuning thin film filter, multi-wavelength and pico-second pulse trains of low chirp could be chosen from the SC spectrum. Amplified spontaneous emission（ASE） induced degeneration of the achieved pulse trains is observed and discussed. 相似文献
20.
GUO Zi-zheng LIANG Xi-xia BAN Shi-liang 《光电子快报》2005,1(3):164-167
In recent years ,the interest in the quantum hetero-structures composed of theⅡ-Ⅵwide gap materials haveincreased dueto potential device applications ,suchasthehigh-brightness blue/green light emitting diodes(LEDs) andlaser diodes (LDs)[1].Sincethe applicationof semiconductor materials to optoelectronic devices re-quires a precise design of the optical properties at theoperation temperature, it is i mportant to have theknowledge of the temperature effects on the opticalproperties of the mat… 相似文献