Journals >Laser & Optoelectronics Progress
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2011
Volume: 48 Issue 1
20 Article(s)
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COHERENCE OPTICS and STATISTICAL OPTICS
Analysis on Large Radius of Curved Surface Roughness Trichromatic Laser Speckle Autocorrelation Measurement
Zhang Jianwei, Yuan Zongheng, and Zhang Yanhua
The influence of curved surface on the method of polychromatic speckle measuring surface roughness is studied by introducing, surface curvature radius. The rough surface and the polychromatic speckle patterns near rough surface are simulated, and the influence of different curvature radii of rough surface on the simulaThe influence of curved surface on the method of polychromatic speckle measuring surface roughness is studied by introducing, surface curvature radius. The rough surface and the polychromatic speckle patterns near rough surface are simulated, and the influence of different curvature radii of rough surface on the simulated speckle patterns and ratio of speckle elongation is discussed. The results show that the factor of curvature radius of rough surface is valid in trichromatic speckle autocorrelation measurement, and the simulated speckle patterns and speckle elongation of rough surface are more similar to those of the straight surface when the curvature radius of the rough surface is larger. The larger the curvature radius is, the larger the speckle elongation becomes, and the smaller the deviation of measured surface roughness is. Therefore, influence of curvature of rough surface on measurement precision should be considered during the measuring process..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10301 (2011)
Detectors
Processing of Noise in Infrared Sensor Made from PMN-PT
Yin Xiaomin, Xu Tingting, Ding Junmin, and Zhang Hua
The new infrared material (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT) has more sensitivities and noises because of its perfect piezoelectric and pyroelectric performances. The characteristic noises in the new infrared sensor are analyzed. We use the algorithm of auto-correlation and wavelet transform to analyze the model of The new infrared material (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT) has more sensitivities and noises because of its perfect piezoelectric and pyroelectric performances. The characteristic noises in the new infrared sensor are analyzed. We use the algorithm of auto-correlation and wavelet transform to analyze the model of readout signal with white noise and 1/f noise at 0 dB simulated by computer. The noise of actual signal is reduced by wavelet transform through field-programmable gate array (FPGA). The result shows that the auto-correlation can only reduce white noise, and the signal-to-noise ratio (SNR) of the signal after de-noise is improved by 5.5 dB. While the wavelet transform can reduce temperature noise, white noise and 1/f noise. The SNR of the signal after de-noise is improved by 15 dB..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10401 (2011)
Fiber Optics and Optical Communications
Analysis on Error Performance of Free Space Optical Communication Based on Turbo Product Code
Hu Hao, Wang Hongxing, Liu Min, Xu Jianwu, and Zhang Tieying
Turbo product code (TPC) is introduced into free space optical communication (FSO) system to mitigate impact of random and long deep fade caused by atmospheric turbulence. After FSO system model is set up, the anti-burst error ability of TPC is studied. Also the algorithm of bit confidence measurement under weak turbulTurbo product code (TPC) is introduced into free space optical communication (FSO) system to mitigate impact of random and long deep fade caused by atmospheric turbulence. After FSO system model is set up, the anti-burst error ability of TPC is studied. Also the algorithm of bit confidence measurement under weak turbulence and Gaussian cascaded channel is derived. The performances of TPC under weak turbulence and influential factors are analyzed. Simulations show that, TPC compensates the losses of random and deep fade effectively and makes coded FSO adapted to different turbulence conditions. To obtain more coding gain, the subcode of TPC should be insured high code rate as a priority, meanwhile its error correction ability should be considered. The number of iteration being 3～4 can achieve good balance between the performance and complexity..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10601 (2011)
Theory and Experiment Research of Double-Knot Resonators Based on Micro-Fiber
Yang Feiya, Wu Yu, Rao Yunjiang, and Chen Yihuai
Series and parallel structures of double-knot resonator based on micro-fiber are analyzed by means of electric field transmission theory theoretically and experimentally. The mathematic model of the two structures is established and data simulation is accomplished by composing gotten mathematic formula on Matlab. In thSeries and parallel structures of double-knot resonator based on micro-fiber are analyzed by means of electric field transmission theory theoretically and experimentally. The mathematic model of the two structures is established and data simulation is accomplished by composing gotten mathematic formula on Matlab. In the experiment, the practical output spectrum of two double-knot resonators is gotten respectively. The experimental result matches theoretical simulation well..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10603 (2011)
Design of Multi-Mode Fiber Collimator with ZEMAX
Lei Pingshun, Xue Lifang, He Jun, Zeng Hualin, Fu Yuegang, and Zhou Yan
A method to design muti-mode fiber collimator by using ZEMAX software is introduced. With the ZEMAX, the theoretical model of the optical system for the muti-mode fiber collimator was built. The zoomy muti-mode fiber collimator was designed and made with artificial optimization. Moreover the simulation results were conA method to design muti-mode fiber collimator by using ZEMAX software is introduced. With the ZEMAX, the theoretical model of the optical system for the muti-mode fiber collimator was built. The zoomy muti-mode fiber collimator was designed and made with artificial optimization. Moreover the simulation results were consistent with the actual results, and confirmed that designing multi-mode fiber collimator is feasible and accurate by ZEMAX. With this model, all kinds of factors on the coupling efficiency and collimation degree of the muti-mode fiber collimator were analyzed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10605 (2011)
Theoretical Investigation on Bistable Switching and Dynamic Characteristics of Tapered Nonlinear Bragg Gratings
Chen Jianjun, Murat Hamit, and Hu Yanting
Based on the coupled mode theory, by using the time-domain transfer matrix method, the bistable characteristics of nonlinear Bragg gratings (NLBG) are analyzed numerically. The results show that under steady case, various tapered factors have a different effects on the threshold switching energy and also positive and nBased on the coupled mode theory, by using the time-domain transfer matrix method, the bistable characteristics of nonlinear Bragg gratings (NLBG) are analyzed numerically. The results show that under steady case, various tapered factors have a different effects on the threshold switching energy and also positive and negative taper can cause the response of optical isolator in NLBG. On the other hand, with the continuous wave taken into consideration, the periodic self-pulsation may emerge extremely easy under the dynamic conditions in NLBG. As the input power increases to the critical intensity, the self-pulsation transforms into the chaos. For a certain tapered factor, the pulsation width and the frequency of the self-pulsation will reduce with the increase of coupling coefficient, but the output state will transform into relaxation damped oscillation when the coupling coefficient reaches a certain value..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10606 (2011)
Image Processing
Experimental Research of Lucky Imaging Technique for Spatial Objects
Liu Qiang, Ren Chengang, Sun Sui, Hu Haojun, and Liang Yonghui
Lucky imaging technique is an image post-processing method based on selecting-recentring-coadding of sequence short-exposure images of objects, which can reduce the influence of image quality because of turbulence-induced imaging motion-blur restoration and reduce the resolution loss. The basic theory and flow of the lLucky imaging technique is an image post-processing method based on selecting-recentring-coadding of sequence short-exposure images of objects, which can reduce the influence of image quality because of turbulence-induced imaging motion-blur restoration and reduce the resolution loss. The basic theory and flow of the lucky imaging are described and the experimental observation of crescent through atmospheric turbulence is reported. Results show that the lucky imaging technique can improve the imaging resolution of spatial objects through atmospheric turbulence. The image enhancement for lucky imaging results based on wavelet transform is processed. The results after enhancement show that the image enhancement technique can improve the imaging resolution farther and the visual effect..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11002 (2011)
Modified MAP Algorithm for Single Frame Super-Resolution Reconstruction
Zhang Lei, Yang Jianfeng, Xue Bin, and Yan Xingtao
The theory of image degraded model and maximum a posteriori probability (MAP) are introduced in brief. Then the defect of the MAP, the constraints of the Gibbs term (the second term of the objective function) to pixels with different gradients unbalanced are analysed. Based on this defect, a modified MAP algorithm for The theory of image degraded model and maximum a posteriori probability (MAP) are introduced in brief. Then the defect of the MAP, the constraints of the Gibbs term (the second term of the objective function) to pixels with different gradients unbalanced are analysed. Based on this defect, a modified MAP algorithm for reconstruction is presented. The gradient matrix gotten from the interpolated image of the low-resolution image to modify the Gibbs term is used, so that the constraints are balanced to some extent. Then the updated MAP objective function is minimized by conjugate gradient method and the modified algorithm is simulated. The results show that, compared with the original MAP algorithm, the modified MAP algorithm can keep details well, and control noise (generated in reconstruction process) greatly in the reconstruction, and the image quality is improved obviously. Meanwhile, the modified MAP algorithm is steady and convergent in solving the problem..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11003 (2011)
Method of Directional Adaptive Filter for Fringe Image
Guo Houkun, Luo Hui, Kevin Xi, and Wu Feng
A novel method of directional adaptive filter for fringe image is proposed based on the investigation of pretreatment method of fringe image on three-dimensional pattern profilometry technique. For a fringe image filter, the direction and the size of filter window are quite sensitive characteristics. The gray values ofA novel method of directional adaptive filter for fringe image is proposed based on the investigation of pretreatment method of fringe image on three-dimensional pattern profilometry technique. For a fringe image filter, the direction and the size of filter window are quite sensitive characteristics. The gray values of the stripe image change periodically in the normal direction, and keep almost the same values in the stripe direction. The fringe direction is calculated by gravity method. The size of data window is automatically adjusted according to the linear dependency to get the correct direction. The length and the width of the filter window are optimized based on the filtering result checking. By this algorithm, it can get the correct stripe direction and the right size parameters of the filter windows, as a result to get the qualified filtered image. This method is verified by the experiments..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11004 (2011)
Imaging Systems
Unwrapping Algorithm with High Noise Immunity
Xu Fuchao, and Xing Tingwen
The phase shifting interference technology is one of the principal methods of high accuracy surface profile measurement. The phase unwrapping is a challenging problem when the pattern contains high level noises and bulk invalid regions. We improve seed-unwrapping algorithm through identifying the residues with combinatThe phase shifting interference technology is one of the principal methods of high accuracy surface profile measurement. The phase unwrapping is a challenging problem when the pattern contains high level noises and bulk invalid regions. We improve seed-unwrapping algorithm through identifying the residues with combination of their three neighborhoods, marking discontinuities before unwrapping and after unwrapping, and recovering the residues and discontinuities with average value of their neighborhoods after unwrapping. The simulation indicates that it is robust for unwrapping of patterns with high noises and bulk invalid regions, and there are no high noisy points in the images unwrapped by the improved algorithm, and the unwrapped images can be well smoothed by average value filter..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11001 (2011)
Instrumentation, Measurement and Metrology
Research on Measurement of High Performance Optical Modulator
Yan Qiang, Huang Yongqing, Duan Xiaofeng, Wang Wei, Yan Xin, Ren Xiaomin, Huang Hui, Wang Qi, and Zhang Xia
Accurate measurement of the high performance photomodulator is increasing in need. A 40 GHz high-speed measurement system has been set up to accurately measure the frequency response of a 35 GHz photomodulator. The main instrument of the system is Agilent′s vector network analyzer (VNA). An error eliminate model has beAccurate measurement of the high performance photomodulator is increasing in need. A 40 GHz high-speed measurement system has been set up to accurately measure the frequency response of a 35 GHz photomodulator. The main instrument of the system is Agilent′s vector network analyzer (VNA). An error eliminate model has been derived to obtain the intrinsic response of the modulator, and the result fits well to the manufacturer report. In addition, the eye diagram of the modulator is measured when the modulator is adjusted to the best work status according to the pre-measured modulator curve. And voltage of pi phase shift is measured using power sweep method. All other important parameters are also measured and analyzed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11201 (2011)
Lasers and Laser Optics
Lasing Mode Stability in Nano-Imprinted Quarter-Wavelength Phase-Shifted Distributed Feedback Laser Diodes
Zhou Ning, Li Linsong, Cao Mingde, Wang Dingli, Wang Lei, Liu Wen, and Li Xun
Based on one-dimensional numerical model for resonant cavity, the dependence of laser spectrum on resonant cavity parameters in quarter-wavelength phase-shifted distributed feedback laser diodes (QPS-DFB-LD) is studied. Comparing theoretical calculation result with measured spectrum, the model parameters of QPS-DFB-LD Based on one-dimensional numerical model for resonant cavity, the dependence of laser spectrum on resonant cavity parameters in quarter-wavelength phase-shifted distributed feedback laser diodes (QPS-DFB-LD) is studied. Comparing theoretical calculation result with measured spectrum, the model parameters of QPS-DFB-LD used in theoretical calculation are given. Simulation results show that the minor deviation of QPS (<10%) cannot affect laser spectrum greatly, but brings a minor blue shift and a slight change on the side-mode-suppression-ration (SMSR). Once the deviation of QPS exists, higher output power will be obtained from the facet closer to QPS region while lower output power will be collected from the other facet. The side of output spectrum SMSR closer to QPS region will be slightly higher. After coating anti-reflective film, residue reflection index of both facets will introduce a drift to the laser mode wavelength within certain range, and will deteriorate the SMSR..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11401 (2011)
Materials
Simulation on Substrate Relative Dilution Ratio for GH4033
Chen Gang, Li Xiangfeng, Zuo Dunwen, Wang Hongyu, and Zhang Min
The concept of relative dilution ratio of the substrate and its calculation formula are suggested in studying multi-pass laser cladding dilution ratio. And the heat effects of the first pass on the second pass and relative dilution ratio of the substrate are discussed in the respective of the cooling time, overlapping The concept of relative dilution ratio of the substrate and its calculation formula are suggested in studying multi-pass laser cladding dilution ratio. And the heat effects of the first pass on the second pass and relative dilution ratio of the substrate are discussed in the respective of the cooling time, overlapping center offset and overlapping ratio. For the GH4033 substrate, it takes 360 s to decrease the heat effect of the first pass on the second pass markedly and to make relative dilution ratio of the substrate near to zero. The larger the overlapping center offset, the less the relative dilution ratio of the substrate is. Overlapping ratio of 50% is appropriate for multi-pass laser cladding..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11601 (2011)
Optical Design and Fabrication
Study on Matrix Properties and Machining Performance of Fixed-Abrasive Pad
Li Suozhu, Zhu Yongwei, Li Jun, Fan Jilong, and Ye Jianfeng
The relationship between different matrix of fixed abrasive pad(FAP) and the polishing performance of K9 glass is studied under the same chemical mechanical polishing process parameters. Swelling ratio and pencil hardness are selected to evaluate the matrix properties of FAP, and material removal rate (MRR) and 3D-profThe relationship between different matrix of fixed abrasive pad(FAP) and the polishing performance of K9 glass is studied under the same chemical mechanical polishing process parameters. Swelling ratio and pencil hardness are selected to evaluate the matrix properties of FAP, and material removal rate (MRR) and 3D-profile surface roughness (Sa) are selected to evaluate machining performance of FAP. The results show that the swelling rate and the pencil hardness of the two substrates together influence the performance of the MRR and surface roughness of the sample. With increasing the swelling rate of matrix, the MRR of sample reduces, and the surface roughness of sample increases; with the increase of wet pencil hardness of the sample, the MRR will also increase accordingly, while the surface roughness of sample based on a value of the swelling rate increases at first and then decreases, and hydrophilic FAP can stand long-time steady processing, which demonstrates the self-conditioning capabilities..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 12201 (2011)
Remote Sensing and Sensors
Surface Plasmon Resonance Sensors Based on Au-Metalized Nanolayer in Microstructured Optical Fibers
Zheng Long, Zhang Xia, Shi Lei, Gao Jing, Ma Huifang, Huang Yongqing, and Ren Xiaomin
Surface plasmon resonance sensors based on Au-metalized nanolayer in microstructured optical fibers are theoretically analyzed by using finite element method. In simulations, the accurate Drude-Lorentz model is used to describe the metal dielectric constant. The numerical results show that as the refractive index of thSurface plasmon resonance sensors based on Au-metalized nanolayer in microstructured optical fibers are theoretically analyzed by using finite element method. In simulations, the accurate Drude-Lorentz model is used to describe the metal dielectric constant. The numerical results show that as the refractive index of the liquid increases, the surface plasmon resonance peak shifts to longer wavelength. The sensitivity of Au-metalized surface plasmon resonance sensor can reach 1200 nm/RIU (refractive index unit) and the corresponding resolution is 8.33×10-5 RIU..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 12401 (2011)
Reviews
Development of Dispersion-Flattened Photonic Crystal Fibers
Dai Nengli, Li Yang, Peng Jinggang, and Li Jinyan
The management and engineering of optical fiber is a necessary factor to be considered in the design of photoelectronic device. As a new kind of light transmission media, photonic crystal fiber (PCF) has an enormous application potential in many fields on account of its large configuration design freedom which makes itThe management and engineering of optical fiber is a necessary factor to be considered in the design of photoelectronic device. As a new kind of light transmission media, photonic crystal fiber (PCF) has an enormous application potential in many fields on account of its large configuration design freedom which makes its performance in the management and engineering of dispersion much more better than that of the conventional communication fibers. Firstly the management of dispersion by changing the geometric structure of PCF and the achievement of flattened dispersion is discussed. After that，the configuration designs of these years to realize flattened dispersion in PCF are emphatically presented, and the applications of its flattened dispersion is also summarized..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10602 (2011)
Optical Hybrids in Coherent Laser Communication
Wan Lingyu, Gu Wei, Wang Rongcheng, and Ma Xuemei
Coherent optical communication is an important technique which improves the sensitivity of receiver and develops a large-capacity and high-rate laser communication system. An optical hybrid is one of the key components of coherent receiver, which mixes the signal with the local oscillator beams and bridges them to deteCoherent optical communication is an important technique which improves the sensitivity of receiver and develops a large-capacity and high-rate laser communication system. An optical hybrid is one of the key components of coherent receiver, which mixes the signal with the local oscillator beams and bridges them to detector for information processing. In this paper, the optical hybrids developed in recent twenties years are surveyed. The principles, configurations and properties of different optical hybrids are introduced and the key techniques are analyzed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 10604 (2011)
Progress on Inorganic Laser Thermal Lithography Materials
Li Hao, Geng Yongyou, and Wu Yiqun
Laser thermal lithography is a new technique developed in recent years, and is used in a number of areas including the manufacture of sub-wavelength nanostructure devices and high density optical disc mastering. Based on thermal change threshold effect of laser thermal lithography materials, the pattern size less than Laser thermal lithography is a new technique developed in recent years, and is used in a number of areas including the manufacture of sub-wavelength nanostructure devices and high density optical disc mastering. Based on thermal change threshold effect of laser thermal lithography materials, the pattern size less than the optical diffraction limit can be fabricated. The fundamental principle, characteristics and requirements for the laser thermal lithography materials are presented. Then the latest research of the phase-transition laser thermal lithography thin films, including chalcogenide phase-change thin films, metal sub-oxide thin films and ceramics composite thin films, thermal decomposition laser thermal lithography thin films and chemical reaction laser thermal lithography thin films is reviewed. In addition, the thermal lithography mechanism of inorganic laser thermal lithography materials is analyzed and summarized, and the development and prospect of inorganic laser thermal lithography materials are discussed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11602 (2011)
Texture Analysis for Information Extraction and Feature Recognition in Optical Coherence Tomography Images
Liang Yanmei, and Zhang Shu
With the development of the optical coherence tomography (OCT) in the field of bio-medical imaging, computer-aided medical diagnosis and treatment effectiveness evaluation by means of the relevant tissue features reflected in the OCT image, has attracted much attention. Among methods aimed at the information extractionWith the development of the optical coherence tomography (OCT) in the field of bio-medical imaging, computer-aided medical diagnosis and treatment effectiveness evaluation by means of the relevant tissue features reflected in the OCT image, has attracted much attention. Among methods aimed at the information extraction and feature recognition in OCT images, texture analysis has already been covered thoroughly and showed a good feasibility. In this paper, we concentrate on the characteristics and applications of various texture analysis methods, followed by the existing problems and possible solutions..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 11701 (2011)
Progress of Terahertz Spectroscopy Detection Technique of Explosives
Wang Gao, Zhou Hanchang, Yao Baodai, Xu Degang, and Yao Jianquan
With the rapid development of the terahertz spectroscopy technique, it has shown great application prospect in the field of safety inspection, aerospace, life science and chemistry. In inspection field, most explosives and related compounds have characteristic absorption and many nonmetal and nonplority materials are tWith the rapid development of the terahertz spectroscopy technique, it has shown great application prospect in the field of safety inspection, aerospace, life science and chemistry. In inspection field, most explosives and related compounds have characteristic absorption and many nonmetal and nonplority materials are transparent to terahertz wave, so it has shown significant potential for the safety inspection and acquired great attention at home and aboard. The abroad and domestic research status of the explosives detection using terahertz spectroscopy technique and the progress of terahertz spectroscopy technique was introduced. Then the the achievements of the solid and gaseous explosives characteristic absorption spectrum were concluded. Finally the existing technique difficulties were summed up and the future development trend was outlooked..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 48, Issue 1, 13001 (2011)
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