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ISSN1001-3806 CN51-1125/TN Map

2003 Vol. 27, No. 5

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Optical packet switching using in-band multi-wavelength label
Xiao Shilin, Zeng Qingji, Wang Jianxin, Jiang Ming, Zhao Huandong
2003, 27(5): 385-389.
Abstract:
A novel packet switching adopting in-band multi-wavelength optical label is introduced,in which optical header is labeled by several optical pulses at different wavelengths in the same optical communication channel band as optical payload.The switching fundamental and its implementation techniques,including optical transmitter with header generation and packet formation,receiver with data restoration and switching node with route processing,are described.A simplified experiment demonstrated the switching principle.
2003, 27(5): 389-389.
Abstract:
Design of a novel electro optical hybrid current transducer
Chai Xiongliang, Cheng Zhaogu, Gao Haijun, Chen Bangdong, Dong Zengping, Li Feng
2003, 27(5): 390-392,395.
Abstract:
A novel electro optical hybrid current transducer is designed.It consists of four parts:a sensor head,an optical fiber transmitter and optoelectric converter,a signal processing circuit and a power supply.In the operation environment,this device has the advantages of high insulation,high reliability,small mass and high inference rejection.Measurement errors are analyzed in this paper.
A new OADM architecture for packet service
Ji Yuefeng, Bai lin, Xu Daxiong
2003, 27(5): 393-395.
Abstract:
In a new OADM (optical add/drop multiplex) architecture for packet service is described. It uses the auto correlation and cross correlation of optical orthogonal codes for address recognition by all optical method. The principle is put into the optical network element. The design method is described and discussed. The application demonstration and simulation are given.
Research of metal-ceramic TiC-B4C-SiC-Co laser cladding on A3 steel
Li Yuhong
2003, 27(5): 396-397,399.
Abstract:
In order to improve the surface performance of A3 steel,we utilize a high power CO2 laser beam to treat TiC-B4C-SiC-Co clad surface. It is obvious that the laser beam scanning speed is a important factor on the structure,hardness and resistance to abrasion of the alloy surface. This paper introduces the experimental research procedure,and the experimental results,which are useful to select the beam scanning and other technical parameters.
Multi-laser beam integration system under computer control
Liu Ming, Chen Xingwu, Yan Yun
2003, 27(5): 398-399.
Abstract:
In the laser application,sometimes it is needed that laser beams of different wavelengths act on the research object at the same time. The integration of laser beams is usually operated manually,and observed and defined by eyes,so that dependability is difficult to be guaranteed. Integration of laser beams under the computer control is to gather each bunch of laser beam signals to the computer and control the reflector to adjust the direction of laser beams.With such a system,the multi laser beams can be integrated effectirely in the practical application.
The new development of laser phacoemulsification
Yu Xiaomin, Chen Huimin, Li Jiaze
2003, 27(5): 400-402,406.
Abstract:
The principles of phacoemulsification on the cataract extraction surgery are presented briefly. Developments on laserphaco are introduced.A few kinds of lasers and their applications are compared.
Effect of the aperture on propagation characteristics of nonuniformly polarized beams
Pan Liuzhan, Lü Baida
2003, 27(5): 403-406.
Abstract:
Based on the beam coherence-polarization (BCP) matrix and the propagation law,the expressions for the degree of polarization and intensity distribution of nonuniformly polarized (NUP) beams through an aperture are derived. Numerical examples for a type of uniform intensity distribution NUP beams are given. It is shown that remarkable changes in both polarization and intensity distributions take place after the aperture. There are oscillations of the degree of polarization at the transversal plane and the intensity profile is nonuniform. However,the polarization becomes uniform in the far field.
Measurement of refractive index of crystals with interferometry
Hao Dianzhong, Wu Fuquan, Kong Weijin
2003, 27(5): 407-408.
Abstract:
Based on the theory of Michelson's interferometer,a new method is used to measure the index of crystals.The theoretical formula is obtained under the condition that the rotating angle is small.Combined with CCD and microprocessor,the measurement precision is improved a lot.
Analysis of fiber Raman laser and multi-wavelength lasers
Yang Xianbo, Liu Deming, Huang Dexiu
2003, 27(5): 409-410,414.
Abstract:
In order to optimize the design of fiber Raman laser,a fiber laser with DCF as gain medium under a simplified model and its output characters are analyzed.Some methods are put forward to optimize the design of fiber lasers.Laser output can be optimized with alterations of fiber length and output coupling coefficient,and the output power can be changed with alteration of pump power.Applying the model to the multi wavelength lasers,four-wavelength lasers have been obtained.
Analysis and numerical calculation of mode conversion efficiencyin collinear acoustooptic interaction
Zhou Yu, Wu Liu, Liu Yongzhi, Zhang Xiaoxia
2003, 27(5): 411-414.
Abstract:
The guided to leaky mode conversion with the induced diffraction grating from the collinear surface acoustic wave (SAW) possess potential application in onboard optical demultiplexing of optic communication systems. This phenomenon is analyzed using the coupled mode theory. Mode conversion efficiency has been calculated as functions of acoustic frequency,interaction length,guiding layer thickness,and acoustic drive power density. It is shown that the x-cut configuration features the highest mode conversion efficiency,measured mode conversion efficiency as high as 90% is obtained at the relevant acoustic drive power density and interaction length.
Effect of loss and chirp on picosecond pulse soliton-effect compression
Wang Runxuan
2003, 27(5): 415-418.
Abstract:
Based on the optical fiber loss,solving the modified nonlinear Schrodinger equations,the paper analyses the function affected by GVD and SPM in single-mode optical fiber in negative GVD area. It quantitatively calculates soliton effect picosecond pulse compression induced by optical fiber loss and initial orthochirp. The result shows that initial orthochirp improves the bad affect of compression factors due to the loss and stops the increase of the best optical fiber length. If an appropriate optical fiber length and initial peak power is selected,efficient compression of orthochirp pulse can be attained in single-mode optical fiber.
Study on transmission laser detection instrument for runway visibility
Shi Deheng, Liu Xinjian, Huang Guoqing, Li Jifang, Zhao Baoqiang
2003, 27(5): 419-422.
Abstract:
This paper presents the principle and measuring method of a laser instrument used to measure runway horizontal visibility and approach visibility. By means of the co operation target,the instrument could simply measure approach visibility,greatly increase amplitude of receiving signal and improve its sensitivity.PIN photodiode can be used as photoelectrical transformation unit to detect the amplitude of receiving signal. By means of transmission ruler,curves of relative errors are optimized. Measurement precision of visibility,especially lower visibility is improved.Measurement error of runway horizontal visibility and approach visibility is less than 12%.
Research and development of the techniques of laser radiationprotection and optoelectronic countermeasures
Luo Zhenkun
2003, 27(5): 423-427.
Abstract:
The general situation of research and development of the technology of laser radiation protection and optoelectronic countermeasures are introduced. The following aspects are included: conventional protective devices for laser,new techniques and materials for protection against laser radiation,laser protection in the photoelectric sensors and the optical windows of weapon equipment,synthesis protection systems against laser radiation,assessment and test for laser protection devices,protective means against laser radiation. Finally,the developing trend of techniques of laser radiation protection is described.
Extra cavity 660nm SHG study of type-Ⅰ noncritical phase-matched LBO crystal
Li Chaoyang, Wang Yonggang, Huang Liu
2003, 27(5): 428-430.
Abstract:
A research detail of Nd:YAG 1.319μm extracavity-doubling using LBO crystal is reported.LBO crystal is adopted by type-Ⅰ noncritical phase-matched(NCPM)and temperature tuned.The experiment shows that using LBO type-Ⅰnoncritical phase-match is effective to get a higher SHG efficiency.With a 1300mJ incident pump laser while temperature is 8.4℃,855mJ 660nm TEM00 mode red laser is obtained,the conversion efficiency is up to 66% and the power instability of output laser is less than ±3%.
SEM-BPM simulation for waveguide modulators
Gan Xiaoyong, Liu Yongzhi, Liao Jinkun
2003, 27(5): 431-433.
Abstract:
Three-dimensional beam propagation method based on the series expansion method(3D-SEM-BPM) transform the BPM into the first-order normal differential equations. The method has the merits of simple calculation and high calculation efficiency. The lithium niobate electro optic waveguide modulator with Mach-Zehnder structure is simulated with this method. We got its optical field distribution and acquired its optimal structure and its power loss curve. The function of tangent is applied to map the infinite space into a finite space to avoid boundary truncation.
Microstructures and properties of laser clad ceramic layers on W6Mo5Cr4V2 high speed steel surface
Xiang Dong, Xu Bin, Liu Kegao
2003, 27(5): 434-436.
Abstract:
The ceramic layers were cladded on W6Mo5Cr4V2 high speed steel surface with a 2kW CO2 laser,and the net of three dimension ceramic layers are formed.The steel was quenched and tempered The test results indicate that the high strength and toughness of the steel combines with their properties of the ceramic layers forming a well distribution. The highesthardness of the layers can reach 1887HV,and the wear resistances are increased (3~7) times compared to those of the steel in common heat treatment. The high temperature hardness and temper stability are enhanced,too.
The research and design of micro-align-lens
Xiong Huaping, Cao Mingcui
2003, 27(5): 437-439.
Abstract:
The refractive index profile of gradient-index (GRIN) lens obeys square rule,as same as multimode-fiber. Based on this fact,the research and design of micro-align-lens which is fabricated by means of multimode-fiber fabrication techniques is carried out. Results show that the micro-align-lens has good performance as single-mode-fiber(SMF) collimator.Compared with GRIN lens,ithas smaller size and can be fabricated simply.
Study on the loss mechanism of the expand beam fiber connector
Su Meikai, Gao Zhiyun, Sun Haidong, Zuo Fang, Liu Bingqi
2003, 27(5): 440-442.
Abstract:
The basic principle expand beam fiber connector is firstly introduced. Then its loss mechanism is analyzed,including the variable loss and the invariable loss. The variable loss comes from the error of leveling for cells of the system,such as the loss of radial excursion,the loss of portrait excursion and the loss portrait obliquity. In all loss,the radial excursion is the greatest,then the loss of portrait obliquity,the invariable loss and the loss of portrait excursion. The invariable loss comes from the materials and surface processing of the system itself,such as the loss of Fresnel,ball aberration,diffraction,chromatic aberration and absorb.Finally,the efficient methods to reduce loss are presented.
Pulsed laser deposition and its application
Chen Chuanzhong, Bao Quanhe, Yao Shushan, Lei Tingquan
2003, 27(5): 443-446.
Abstract:
Thin film materials have been widely used in micro electronics,superconductor,and bioceramics materials. In order to obtain high quality thin films,deposition have attracted more attention. In this paper the principle,the characteristics of the pulsed laser deposition technique are introduced. Its applications in semiconductor,high temperature superconductor,diamondlike,ferroelectric and bioceramics thin films and its current research status are reviewed. The future application trend is prospected.
The recurrence algorithm of Hermit-Gaussian beams through a paraxial optical system with an internal hard-edge aperture
Tao Xiangyang, Tu Haihua
2003, 27(5): 447-449,452.
Abstract:
A recurrence propagation formula of Hermit-Gaussian(H-G) beams through a paraxial optical ABCD system with an internal hard edge aperture is derived,from which the analytical propagation equation of H-G beams of any orders can be obtained,and the effect of the aperture on the propagation can studied analytically. Numerical examples are put forward to illustrate the application and advantage of our analytical results.
Rods’matching and coupling of multi-rod solid-state laser
Zhu Guangzhi, Chen Peifeng, Zhou Zhuoyou, Huang Weiling, Zou Xuefen
2003, 27(5): 450-452.
Abstract:
Based on optical transmission matrix,multi-element thermal lens resonator is analyzed. The way to adjust rods' matching and coupling is presnted. Theoretical analysis is accordant with the experiment results. For three rod serial CW Nd3+:YAG laser,the stable output power between (0~1)kW is acquired.
Study on pulsed laser deposition technology
Ao Yuhong, Hu Shaoliu, Long Hua, Xu Yebin, Wang Youqing
2003, 27(5): 453-456,459.
Abstract:
The processes of pulsed laser deposition(PLD) technology,one of the most attractive thin film preparation methods,are described. The properties are listed in contrast with other methods. The fundamental approaches and the latest appropriate developments in PLD with ultra-fast pulsed laser,pulsed-laser-arc,and dual-beam lasers are discussed in detail.
Experimental research of the ablation threshold of Kevlar/epoxy
Wang Guibing, Liu Cangli
2003, 27(5): 457-459.
Abstract:
The surface reflectivity of Kevlar/epoxy doesn't change when there are no chemical and physical changes of the composite reinforcced by polyaryl amide fibers irradiated by laser beam.However it will change.The ablation threshold of the material can be obtained by monitoring its surface reflectivity changes using integrated spheres and photodiode system.This method can trace the increase of the laser power to get the ablation threshold of the material.This paper has proved the feasibility of this method by measuring the threshold of the composite reinforced by polyaryl amide fibers irradiated by laser beam with a wavelength of 1.06μm.
Experimental study of laser milling of silicon wafer
Yuan Genfu, Zeng Xiaoyan
2003, 27(5): 460-462,465.
Abstract:
Experimental study of laser milling were carried out on the surface of silicon wafer with different YAG lasers and laser processing parameters. The effect of laser processing parameters on the milling surface quality were studied systematically. Different shapes and structures were fabricated on the surface with the optimized procedures.
Laser beam classification
Peng Yuanjie, Lü Baida
2003, 27(5): 463-465.
Abstract:
The laser beam classification,a very interesting subject in laser optics,is reviewed and analyzed. Based on the second order moment method and Wigner distribution function,and in accordance with their spatial symmetry,laser beams can be classified as three types,i.e. stigmatic (ST) beams,simple astigmatic (SA) beams and general astigmatic (GA) beams. On the other hand,according to their spatial coherence,there are two types of laser beams,namely,partially coherent beams and fully coherent beams. The independent characteristic parameters of different types of laser beams and their relation are analyzed.
15kW constant-voltage current-limiting switching power supply for YAG pulse laser
Ma Xinmin, Guo Zejun, Cao Hongbing, Wang Min, Huang Weiling
2003, 27(5): 466-469.
Abstract:
A 15kW switching power supply with the function of constant voltage current limit for YAG pulse laser is presented. In this paper,the operation principle of the control circuit is discussed,and the implemented circuit is also described. Analytical and experimental results prove that the power supply has good static characteristics,fast dynamic response and high reliability. Furthermore,the configuration is simple and the cost is low.
Interference of two beams in a He-Ne laser with optical feedback
Liu Gang, Zhang Shulian, Zhu Jun, Li Yan
2003, 27(5): 470-472.
Abstract:
This article makes a research in theory and experiment on the changes of the interference signal and the laser intensity of an interferometer with optical feedback in a He-Ne laser.When the main feedback mirror moves,the curve of the laser output intensity is a sine wave but the interference signal is a curve with two peaks in a period.One peak is higher than the other one.When the feedback mirror changes its moving direction,the order that the two peaks come out will change too.The article analyses the experimental results in theory and simulates the interference signal and the laser intensity signal.The simulation results are in good agreement with the experiment results.A measuring method is discussed which can judge the moving direction of the moving object easily and this method is easy to be realized.
Rigorous vector analysis of diffractive micro-cylindrical lenses’characteristics of focal depth and focal shift
Feng Di, Yan Yingbai, Jin Guofan, Tan Qiaofeng
2003, 27(5): 473-476.
Abstract:
The vector diffraction characteristic must be considered to diffractive optical elements whose features are on the order of or smaller than the wavelength of the incident illumination. We present the rigorous vector analysis of diffractive micro cylindrical lenses that are finite in extent using a two-dimension finite-difference time-domain (FDTD) method. Using these effective analysis tools,lens' characteristics of focal depth and focal shifthave been analyzed rigorously. The results are compared with the scalar theory and the effects of quantified profiles are presented,respectively. Minimizing the numerical dispersion in the FDTD calculation region,setting the absorbing boundary and calculating the steady state electromagnetic fields' propagation from the FDTD region to the observation plane has been discussed in detail.
2003, 27(5): 476-476.
Abstract:
Analysis of fluorescence spectra of alcohol and its characteristic
Lan Xiufeng, Liu Ying, Gao Shumei, Shen Zhonghua, Lu Jian, Ni Xiaowu
2003, 27(5): 477-479,483.
Abstract:
The fluorescence spectra of alcohol solution induced by ultraviolet light and its characteristic are studied experimentally and theoretically in this paper. The results show that alcohol solution can emit strong fluorescence at 395nm when excited by ultraviolet light with the wavelength of 254nm.It is considered that this fluorescence comes from the transition from n→σ* of the lone-pair electrons in the hetero atom group (C-OH) of the ethanol molecule. Investigation on the fluorescence spectra and its characteristics will contribute to study of other organic macromolecule fluorescence spectra when alcohol serves as solute.
Simulating uniformity of film thickness with finite-elements method
Tan Xudong, Ma Zi, Cai Bangwei
2003, 27(5): 480-483.
Abstract:
In this paper,finite-elements method is used to simulate the film thickness uniformity at different rotation and different time. The result shows that the uniformity of film thickness can be improved if the rotation and time are selected properly.
CW and pulse CO2 laser frequency stability measurement experiment
Cheng Xiangyang, Wang Qi, Tian Zhaoshuo, Lu Wei
2003, 27(5): 484-485,489.
Abstract:
The frequency stability of CW CO2 laser was measured with beat frequency method.A computer received data directly from a counter through IEEE488 interface,then calculated the laser's frequency stability.A pulsed CO2 laser's frequency stability was measured with pulse beterodyne method.
Discussion on laser welding combined with other heat resources
Liu Jichang, Li Lijun, Zhu Xiaodong, Chen Hong
2003, 27(5): 486-489.
Abstract:
This paper introduces several methods of laser welding combined with other heat resources,and investigates why they decrease or eliminate the drawbacks of laser welding while embodying its advantages. We can draw a conclusion that laser welding combined with other heat resources is a trend of laser welding development.
Transformation of cosh-Gaussian beams passing through a multi-apertured optical system
Kang Xiaoping, Ji Xiaoling, Lü Baida
2003, 27(5): 490-492.
Abstract:
Based on the expansion of the window function of a hard edge aperture into a finite sum of complex Gaussian functions,the recurrence propagation equation of cosh Gaussian(ChG)beams through a multi apertured paraxial ABCD optical system is derived,which permits us to study the propagation of ChG beams through hard edge optics analytically.Numerical results are given and compared with those derived by the straightforward integral of the Collins formula,which shows the advantage of saving the computer time greatly by means of our analytical formula.
Laser treatment of law blade
Yang Jiuxia, Zhang Jianyu, Wu Diping, Wu Zhangdong, Lü Baomin
2003, 27(5): 493-496.
Abstract:
Aiming at the exist problem of saw blade made in Laiwu Steel and Iron Co.saw blade treated by laser was studied in the paper.The result proved that the hardness and anti-abrasion of the saw teeth are increased,the vibration and stability of the saw blade were improved which were heat-treated by laser,so the longevity of saw and quality of sawing can be ensured easily.