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2009 Vol.30 Issue.1, Published 2009-01-10 OE Information Acquisition and Processing OE System and Engineering Optical Element and Fabrication Fiber Sensing and Optical Communication   OE System and Engineering 50 Real-time wavefront reconstruction based on diffraction grating wavefront curvature sensor SHEN Hong-bin;ZHANG Chu;SHEN Xue-ju;SUN Yu-jie;HUANG Fu-yu;YAN Zong-qun Adaptive optical systems require the wavefront sensors to realize real��time dynamic measurement, and the wavefront curvature sensing technology can meet such requirement. A novel wavefront curvature sensor based on the twisted diffraction grating has a greater advantage in the realization of detecting device, and its wavefront reconstruction algorithm is used for the measurement of optical surfaces. The numerical simulation of the detection signal was implemented with the theory of diffraction optics, and the numerical simulation of the wavefront reconstruction was realized with Green function algorithm under Neumann boundary conditions. The results indicate that the speed of Green function algorithm is fast, it meets the requirement of the real-time wavefront reconstruction, and the result of wavefront reconstruction for low-order Zernike polynomials is good. The analysis shows that the major source of wavefront reconstruction error is the boundary noise in the gradient of light intensity. 2009 Vol. 30 (1): 50-55 [Abstract] ( 0 ) [HTML 0KB] [ PDF 772KB] ( 0 ) 56 Characteristics of beam splitter based on 1×4 photonic crystal waveguide LIU Qiao-qiao;XU Xu-ming;LI Hong;LIANG Xiao-jun The beam splitter based on photonic crystal waveguides is taken as an essential component in integrated optical circuits. A linear-defect 1×4 photonic crystal splitter was designed, and its characteristics were analyzed with the time-domain finite difference method. The experiment results show that the transmission properties at output end is dependent on the wavelength of incident light and the geometric shape of the branch, and the incident wave is divided equally into four output ports. The high transmittance can be obtained at each output port by adjusting the radii of the medium in the branching region to reduce the reflection of the 1×4 splitter at the three Y-branching regions. 2009 Vol. 30 (1): 56-59 [Abstract] ( 0 ) [HTML 1KB] [ PDF 579KB] ( 0 ) OE Information Acquisition and Processing 60 Data acquisition in multi-sensor electro-optical tracker LIU Jian-ping;LU Pei-guo;CHENG Li;XU Li-rong;HAO Li-feng The data acquisition in a multi-sensors electro-optical tracker, which includes TV, FLIR, laser rangefinder and fiber gyroscope, was implemented with a digital signal processor and a multi-bus architecture. CPCI bus technique combined with dual port RAM was incorporated to realize high-speed information transmission within the system. It can provide the servo control system with reliable data for fully digitalized control, high-precision sight stabilization, fast and accurate tracking, and improve the performance of the electro-optical tracker effectively. The design scheme and operation principle of the data acquisition system are presented. The control mode and interface design of each sensor in the system are studied. The data transmission between all of the sub-systems is described briefly. 2009 Vol. 30 (1): 60-64 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 65 Tracking method of ��S maneuver�� target WANG Xiao-tian;JIA Yu;CHEN Fang-bin In order to enable the electro-optical tracking systems to track the ��S maneuver�� targets, a model with the extended Kalman filtering algorithm against the maneuvering target turn is proposed based on the motion characteristics of ��S maneuver�� targets to overcome the shortcomings of the previous Singer model. The precision tracking for the ��S maneuver�� targets in 2-D plane was realized by the Monte Carlo simulation, and the root mean square error of position is much smaller than the Singer model. It proves that this method is capable of tracking the typical ��S maneuver�� targets. 2009 Vol. 30 (1): 65-68 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) Opcical Metrology and Measurement 69 Quantitative evaluation for wavefront of optical elements with digitized Foucault tester WANG Xiao-peng;ZHU Ri-hong A digital knife-edge test system is proposed based on the traditional Foucault tester. Quantitative evaluation for the wavefront of spherical optical elements was achieved by using this test system. The system configuration, principle and testing process are described in the paper. The surface of a spherical optical element with the radius of 1000mm and the aperture of 160mm was tested with the test system. The measured RMS and P-V values of the wavefront error of the optical element under test are given. The measured results are discussed. 2009 Vol. 30 (1): 69-72 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 73 Measuring method of angle-measurement precision for fire control dynamic performance test system ZHANG Kai;FU Yue-gang;WANG Zhi-jian Distortion of optical system makes focal length of advanced fire control dynamic performance test system different at different FOVs, and influences angle-measuring precision. A focal length calibration formula based on least��square method was used to obtain a unified focal length for all the FOVs and the influence of the distortion was reduced. For a specific fire control dynamic performance test system, its measurement result was 2.34�� by using the method, which improved angle precision from 20 to 5 arc-second. It is proved that the modified calibration formula can improve the performance specification of fire control dynamic performance test systems. 2009 Vol. 30 (1): 73-75 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 76 Measuring thin-film thickness with phase-shift interferometry SHI Yi-lei;SU Jun-hong;YANG Li-hong;XU Jun-qi High-precision measurement of thin-film is a precondition for the process optimization and diagnositcs in the thin-film preparation. Interferometric metrology is a widely accepted high-precison measurement technology which takes wavelength as the measurement unit. A novel measurement method of thin-film thickness based on phase-shift interferometry is presented. The precision measurement for the thickness of SiO2 thin-film sample was realized after the phase unwrapping and data processing for the obtained interferogram were implemented. The results show that this method has the advantages of noncontact and high accuracy, and the PV and RMS values of the measured thin-film thickness are 0.162��m and 0.043��m respectively. 2009 Vol. 30 (1): 76-79 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 80 Improved method for intersection measurement with two photoelectric theodolites XIANG Shu-lin;XU Ning A new method for locating target with two photoelectric theodolites is presented. The real-time calculation of the parameter accuracy was performed by the method based on the common locating formula. The weight coefficient is dynamically determined according to the accuracy variation of resolved ballistic parameters. The simulation result shows that the coordinate measurement accuracy is improved in the case of the intersection locating with two theodolites of different accuracy. 2009 Vol. 30 (1): 80-83 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 84 Sensitivity analysis of ellipsometric parameters in ellipsometric spectral measurement HUANG Shui-hua;ZHOU Quan;TAN Ji-chun Based on a brief introduction of the basic principle of ellipsometry and some derivations, the sensitivity of ellipsometric parameters with respect to film parameters and the influence of incident angle on the ellipsometric parameters were discussed, and its simulation analysis was made. It shows that the sensitivity of ellipsometric parameter Delta to the film optical constants and film thickness is apparently higher than another ellipsometric parameter Psi, and the measurement accuracy of ellipsometric parameter Delta directly affects the fitting accuracy of film optical constants and film thickness in the ellipsometric data processing. A method is provided to improve the measurement accuracy of Delta by choosing the incident angle close to the Pseudo-Brewster Angle. 2009 Vol. 30 (1): 84-88 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 89 Measurement of beam-splitting ratio and insertion loss of Y-waveguide XIE Qi;XU Rong-guo;FAN Ji-hong;YANG Ye-ping;YANG Zhao-jin Y-waveguide is widely used in the integrated optics, and it is important to know its specifications, among which the beam-splitting ratio and insertion loss are the most critical parameters. The measurement setups and methods for the two parameters are introduced. As for the beam-splitting ratio, the output luminous power for two tail fibers of Y-waveguide was measured respectively by using two sources with wavelengths at 1300nm and 1550, and the primary factors which affected the measurement were analyzed and the uncertainty was evaluated after working out the beam-splitting ratio according to the formula. As for the insertion loss, the measurement setup was built up based on the measurement principle, and the factors which affected the measurement of the insertion loss were theoretically analyzed. 2009 Vol. 30 (1): 89-92 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) Optical Element and Fabrication 96 Quality control in large-aperture laser glass optical processing ZHANG Bao-an;CHEN He-ming;ZHU Jian-qiang The characteristics of Large-aperture laser glass optical processing are precise, difficult and time consuming. Quality management is necessary in large-aperture laser glass optics processing to insure the fabrication quality. The paper elaborated the quality control method in large-aperture laser glass optics processing. By implementing this quality management, the qualification rate and processing efficiency of large-size glass optical laser has been enhanced. 2009 Vol. 30 (1): 96-100 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 101 Uniformity of photoresist film coated on concave sphere ZHAO Jing-li;WANG Hui-qing;FENG Xiao-guo;LIANG Feng-chao The flow mechanism of the photoresist on the concave sphere under centrifugal state is elaborated by the analysis of the photoresist coating process with centrifugation force. The critical factors that affect the evenness of photosensitive resist and the film forming quality, such as viscosity of photoresist solution, velocity of spin coating and time of spin coating, are investigated with experiments. The various phenomena occurred due to these factors are listed and analyzed theoretically. A mathematic model which describes the relationship between layer thickness and velocity is established by quoting the formula for the spin coating of photoresist film on the concave sphere. The effect of the fluid speed on the uniformity of the layer in the limited circular space is explained according to the principle of fluid mechanics. Accordingly��the key technology for preparing microstructure patterns on the concave spherical surface is achieved. 2009 Vol. 30 (1): 101-104 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 105 Ellipsometric analysis of optical constants for diamond-like carbon films deposited by UBMS LI Qian;HANG Ling-xia;XU Jun-qi The optical constants of diamond-like carbon (DLC) films deposited by UBMS were measured and analyzed with a broadband ellipsometer. Based on the models established previously and the analysis on it, the model structure was analyzed and adjusted according to the film forming characteristic of the DLC film. Considering the effects of surface roughness, film surface, substrate surface and interface factors on the measured result, the surface and the DLC film was divided into two layers during modeling because of its graphitization on the surface, and their effects were approximately processed with the effective media approximation (EMA). The results indicate that the ellipsometric data MSE of DLC films deposited on the silicon substrate by UBMS was reduced from 37.39 to 4.061 by this model. The measurement accuracy was improved. 2009 Vol. 30 (1): 105-109 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) Fiber Sensing and Optical Communication 110 Objective lens design of fiber image-transmitting bundle CHEN Yue-cun;TANG Yong The structures and applications of three telecentric systems in the image space are described. The traditional single group telecentric structure in the image space and ��negative-positive�� telecentric structure in the image space were made respectively during the design of the objective lens for the fiber image-transmitting bundle. The two schemes were compared. It is found that the ��negative-positive�� telecentric structure in the image space meets the demands of the off-axis aberration correction and image plane illumination uniformity at its image plane, and makes the lens compact. After the optimization with the optical design software Zemax, a designed lens sample is fabricated, whose operation wavelength, focal length, FOV and relative aperture are 0.38��m-0.78��m, 1.92mm, 60�� and 1��4 respectively. The result shows that MTF value of the lens is greater than 0.8 at the spatial frequency of 46lp/mm. 2009 Vol. 30 (1): 110-113 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 114 Multi-parameter monitoring system based on FBG for bridge structure WU Zhao-xia;YAN Dong-mei;LI Zhi-quan Proceeding from the practical application of civil engineering, an all-grating low-cost distributed sensing system for simultaneous measurement of temperature, strain and pressure based on the optic Bragg grating (FBG) is proposed by using the multiplexing and wavelength abslute coding features of the FBG sensor. A FBG multi-parameter monitoring system for the bridge structure was designed based on continuous wave modulation frequency technology. The address of distributed FBG sensing network was realized by combining optical frequency domain reflectometry (OFDR) with wavelength division multiplexing (WDM), and the content of multiplexing was increased. The experiments show that the system can accurately monitor the internal strain of the important parts of bridges, and provide the precision data for static and dynamic load testing of bridges. 2009 Vol. 30 (1): 114-117 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 ) 118 High-durable smart steel tie rod based on FBG absolute measuring technology HE Jian-ping;ZHOU Zhi;WANG Yong-zheng;OU Jin-ping In view of the lack of effective methods for the measurement of internal force under the construction loads and the long-term monitoring in service of steel tie rods, a novel high-durable smart steel tie rod based on the fiber Bragg grating (FBG) absolute measuring technology and packaged by glass fiber reinforced plastic (GFRP) was developed. The strain detected by the FBG strain sensors has a very good linearity and repeatability under 85% tensile load of the theoretical yield load, and the measured rod force agrees well with the stretching force (relative error ��4%). The advantages of the smart steel tie rod, such as durability, anti-corrosion, electro-magnetic resistance, low cost and absolute measurement, were verified. It can indicate the state of stress in any phase, and can be regarded as a large strain load sensor used to measure the stress of the steel tie rod or some components adjacent to it. It is suitable for monitoring the stress exerted on the steel tie rod sturctures serviced in harsh environment. 2009 Vol. 30 (1): 118-124 [Abstract] ( 0 ) [HTML 0KB] [ PDF 0KB] ( 0 )

Supervised by China Association for Science and Technology Sponsored by Chinese Association of Automation NationalResearchCenter for Intelligent Computing System Institute of Intelligent Machines, Chinese Academy of Sciences Published by Science Press

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