Journals >Acta Photonica Sinica
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2017
Volume: 46 Issue 11
30 Article(s)
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Fiber-Coupled Acousto-Optic Modulator System with Wide Frequency Tuning
CHEN Jiang, RUAN Jun, LIU Dan-dan, WANG Xin-liang, WANG Xin, and ZHANG Shou-gang
The system adopts the scheme of double pass acousto-optic modulator configuration and "cat′s eye" structure, which eliminates the optical path deflection caused by frequency modulation and increases the tuning range of the laser frequency. Meanwhile, for the purpose of reducing the power fluctuations, we haveThe system adopts the scheme of double pass acousto-optic modulator configuration and "cat′s eye" structure, which eliminates the optical path deflection caused by frequency modulation and increases the tuning range of the laser frequency. Meanwhile, for the purpose of reducing the power fluctuations, we have constituted a feedback loop by using the method of radio frequency drive power. Through the theoretical calculation and experimental verification, the system chooses the lens with the focal length of 40 mm. When the laser frequency is tuned at 160 MHz, the overall fiber coupling efficiency is 56.8%. To ensure that the overall system utilization of laser is greater than 15%, the system′s effective frequency tuning range of 100 MHz.Through the power stabilization system, we have achieved the stability of ±0.07% with the frequency tuning range of 60 MHz and can maintain long-term stable operation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1106001 (2017)
Effects of Spatial Electrons on Signal-Noise-Ratio of a X-ray Communication System
LI Yao, SU Tong, SHENG Li-zhi, QIANG Peng-fei, XU Neng, LI Lin-sen, and ZHAO Bao-sheng
A model of electron interacting with nested X-ray focusing optics was designed firstly. Then the process of electrons interacting with coating material of X-ray focusing optics and the quantum efficiency of X-ray source by using a Monte Carlo N Particle transport code was analysized. Simulation results accord well withA model of electron interacting with nested X-ray focusing optics was designed firstly. Then the process of electrons interacting with coating material of X-ray focusing optics and the quantum efficiency of X-ray source by using a Monte Carlo N Particle transport code was analysized. Simulation results accord well with the analyze results. Finally, a silicon drift detector, which has an energy resolution of 125 eV was used to analysis the energy spectrum in the focal point. In the detecting part, X-ray photons are composed of two parts, signal photons generated by the X-ray source and noisy X-ray photons generated from nested X-ray focusing optics′ coating material. According to different conditions of X-ray source and electron gun voltage, the number of signal photon, noisy photon and signal to noise ratio of the X-ray communication demonstration system then can be calculated. Experiment and calculate results show that nested X-ray focusing optics can effectively filter spatial particles, which will optimize the signal to noise ratio of X-ray communication system. When the number of incident electrons is about 1×108 counts per second with an energy distribution from 1~20 keV, signal to noise ratio of the X-ray communication demonstration system can reach at least 15.1 dB. These results will provide foundations for optimizing the core parameters of X-ray communication system in the future..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1106002 (2017)
Design and Performance Analysis of a Fiber Optic Ring Heat-off Spool
YANG Han-rui, YANG Yan, HUANG Wei-liang, LIU Jing-jing, and LI Yong-yong
A sensor head design scheme by adding a heat-off spool to the fiber coil is studied to improve the Fiber Optic Current Sensor (FOCT) temperature performance which is vital to the precision of FOCT. The discretized mathematical model of the output error of the FOCT system is deduced and established based on the thermal A sensor head design scheme by adding a heat-off spool to the fiber coil is studied to improve the Fiber Optic Current Sensor (FOCT) temperature performance which is vital to the precision of FOCT. The discretized mathematical model of the output error of the FOCT system is deduced and established based on the thermal phase difference caused by the temperature disturbance of the fiber coil. Then, the finite element model of the fiber coil itself and the fiber coil with the heat-off spool is established respectively by using the finite element analysis software, and the thermal performance of the heat-off spool and the temperature performance of the FOCT with new sensor head under different temperature loading schemes are simulated and analyzed. Simulation results show that the heat-off spool actually can control the temperature change range of each fiber in the fiber coil, slow down the temperature change rate of the fiber, equalize the temperature field of the fiber coil. Besides, the output error range of FOCT system with the proposed sensor head is obviously reduced, and the system measurement accuracy be improved effectively, which is important for the high-precision FOCT′s production and application..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1106003 (2017)
Depth Measurement of Scratches on the Curved Surface Based on Light-sectioning Method
LI Hui-peng, L Ya-ning, SUN Ye-fei, TANG Ruo-xiang, and LIU Bin-yan
A method for depth measurement of scratches on the curved surface using light-sectioning method is presented, which can improve the accuracy of scratches measurement compared with traditional light-sectioning method. The shortcomings of the traditional light-sectioning method were analyzed and the error of the scratcheA method for depth measurement of scratches on the curved surface using light-sectioning method is presented, which can improve the accuracy of scratches measurement compared with traditional light-sectioning method. The shortcomings of the traditional light-sectioning method were analyzed and the error of the scratches measurement on the curved surface was modeled and simulated. The results of the analysis and the simulation show that the error of the scratches on the curved surface varies with the radius of curvature and the width of the scratches using traditional light-sectioning method. The precision parts with different radius were selected in the experiment and the scratches on the curved surface were measured. Comparing with the large error of the conventional light-sectioning method, the accuracy of the results measured by this new method is higher when the radius of curvature is smaller and the width of the scratch is larger. The error of measurement less than 1mm can be reduced by this new method when the radius of curvature is less than 10 mm and the scratch width is greater than 283 mm. This method can be applied to the depth measurement of scratches on the curved surface of the precision instrument..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112001 (2017)
Measurement of the Spectral Characteristic Parameters of Linear Variable Filters
WANG Shi-feng, YUAN Yan, SU Li-juan, and AN Da
In order to accurately measure the spectral characteristic parameters of Linear Variable Filters (LVF), a method of measuring the transmission of LVF was presented. In this method, the spectral transmission at the measurement point was calculated by measuring the spectral signal of light source and transmitted light wiIn order to accurately measure the spectral characteristic parameters of Linear Variable Filters (LVF), a method of measuring the transmission of LVF was presented. In this method, the spectral transmission at the measurement point was calculated by measuring the spectral signal of light source and transmitted light with a spectrometer. By adjusting the displacement platform, the spectral transmission at different positions was measured.Then the spectral characteristic parameters of LVF was obtained by data processing. The theoretical formula for measuring the spectral transmittance was deduced.The simulation results show that the accuracy of this method decreases as the linear dispersion increases. When the linear dispersion is less than 1.5 nm·mm-1, the errors of the measured center transmission and bandwidth are less than 0.4%. An experimental setup was built to test the spectral parameters of a linear variable filter..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112002 (2017)
Research on the Calibration Method of MCT Analogy Detector Quantum Efficiency
SHENG Wen-yang, LI Jian-jun, XIA Mao-peng, and ZHENG Xiao-bing
The measurement facility based on parametric down-conversion technique is established to measure the quantum efficiency of the infrared analogy detector. Uses the CW laser beam of 2 576.5 nm wavelength tuning out of Optical Parametric Oscillator (OPO) laser as the pump source and the ZnGeP2 crystal as the nonlinear cryThe measurement facility based on parametric down-conversion technique is established to measure the quantum efficiency of the infrared analogy detector. Uses the CW laser beam of 2 576.5 nm wavelength tuning out of Optical Parametric Oscillator (OPO) laser as the pump source and the ZnGeP2 crystal as the nonlinear crystal, obtained the correlated photon pairs of 3.42 μm and 10.4 μm. The charge amount of the collected photo-current/voltage signal is converted into the equivalent photon counting, and the dual channel data fluctuation is carried out for the average photon counting of each mode through the method of double light path balance measurement, realized the absolute power responsivity calibrated of an MCT infrared detector at 10.4 μm, the results show a relative combination uncertainty of about better than 4.53% for this calibration method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112003 (2017)
Error Analysis of Vision Measurement Based on the Light Field Camera
WANG Yi-zhi, ZHANG Xu-dong, XIONG Wei, and DENG Wu
Light field camera can obtain position information and direction information of space target through one exposure. It has the characteristics of refocus and multi-view, which can be used for vision measurement. In this paper, the measurement principle and error influence factors of epipolar plane image (EPI), refocus-bLight field camera can obtain position information and direction information of space target through one exposure. It has the characteristics of refocus and multi-view, which can be used for vision measurement. In this paper, the measurement principle and error influence factors of epipolar plane image (EPI), refocus-based, binocular and trinocular measurement methods were analyzed. The relationship between the measurement errors and the structural parameters, including the baseline length of different views, the focal length of the main lens and the actual distance of the target from the camera, were verified by experiments. Theoretical analysis and experiment results show that, due to the short baseline of the camera, the distance measurement errors are large, and short distance is of high precision; under the condition of fixed size of microlens array, the multi-view combination measurement method has higher accuracy..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112004 (2017)
Test Method of Angle Error of Limited Rotation Axis System
TIAN Liu-de, ZHAO Jian-ke, ZHOU Yan, WANG Tao, ZHAO Huai-xue, PAN Liang, and LIU Zhao-hui
In order to improve the measurement accuracy of the angular error in the limited rotation axis system, the principle and method of measuring the angular error by autocollimation theodolite was used to analysis the error sources which affect the measurement result, the simulation results show that the tilt angle of the In order to improve the measurement accuracy of the angular error in the limited rotation axis system, the principle and method of measuring the angular error by autocollimation theodolite was used to analysis the error sources which affect the measurement result, the simulation results show that the tilt angle of the axis of the measured shaft is the main error source. Based on the accurate error model, the method to identify the misadjustment parameters and separate the introduced error by using the least squares estimation was proposed to realize the high precision measurement of angle error. The experiment was carried out with the accuracy of 2″ single-axis position turntable as tested object. The test results of conventional methods are －309.1″~428.6″, the test error is large, however, the test results of the proposed method are －0.89"~1.01"and －1.01″~0.93″, the test error is 0.70″ and 0.78″, eliminating the test error introduced by equipment misadjustment. The method has the advantages of simple equipment and simple operation, and can realize the high precision measurement the angle error of the limited rotation axis system, can solve the problem of limited rotation axis systemengineering testing problem..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112005 (2017)
Rapid Glass Refractive Index Measurement Method Based on Machine Vision
LI Yan-feng, LI Xiu-yu, and YANG liu
A measurement method of glass refraction rate based on machine vision technology is put forward, to achieve fast and high precision measurement requirements of glass refractive index. A mathematical model for measuring the refractive index of glass, the self-collimator can realize the function of the traditional V prisA measurement method of glass refraction rate based on machine vision technology is put forward, to achieve fast and high precision measurement requirements of glass refractive index. A mathematical model for measuring the refractive index of glass, the self-collimator can realize the function of the traditional V prism collimation, which calibrate the V-slot clamping posture. The large field of stitching is achieved by dual CCD and prismatic decomposition. The angle of the refracted light is directly measured by digital image technology. Finally, the test prototype is established, which is test and verified with traditional V prism refractometer and the digital V prism refractometer in the measurement accuracy and measurement time of glass refractive index, the results show that the measurement accuracy is better than ±2×10-6and measurement speed is better than 10 s, Whether both the measurement accuracy and the measuring time is better than before. It has important practical significance to realize fast and high precision measurement of refractive index of optical glass..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1112006 (2017)
Generating Long-Distance Nondiffracting Bessel Beams with Liquid-immersion Composite-Axicon
LIU Liang, HUANG Xiu-jun, XU Hong-yan, SONG Zhen-jiang, SHI De-le, and WANG Shan-shan
A composite axicon is presented, which consists of a positive axicon and a negative axicon immersed in index-matching liquid. Analysis results show that it is equivalent to conventional positive axicon, and can be used to generate long-distance nondiffracting Bessel beam.The maximum distance without diffraction dependsA composite axicon is presented, which consists of a positive axicon and a negative axicon immersed in index-matching liquid. Analysis results show that it is equivalent to conventional positive axicon, and can be used to generate long-distance nondiffracting Bessel beam.The maximum distance without diffraction depends on not only the refractive index of axicons and index-matching liquid, but also the cut angle of axicons. Therefore, it is a flexible method which not only increases the selection of element material, but also reduces the difficulties of element processing..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1114001 (2017)
The Fast Algorithm of Auto-lalignment Based on Spot Shape
LI Hong, LIN Qiang, YANG Peng-qian, ZHANG Yan-li, LIU Dai-zhong, ZHU Bao-qiang, and ZHU Jian-qiang
To meet the accuracy of the high power lasers auto-alignment system, a new method of elliptic light spot differential quick adjustment in the state of non-vertical was put forward, introducing the local adaptive threshold and binarization algorithm which improve the auto-alignment system positioning accuracy of the imaTo meet the accuracy of the high power lasers auto-alignment system, a new method of elliptic light spot differential quick adjustment in the state of non-vertical was put forward, introducing the local adaptive threshold and binarization algorithm which improve the auto-alignment system positioning accuracy of the image .When the axle differential is big the ellipse fitting based on least square method is improved to calculate the length of ellipse light spot major axis and minor axis, and to adjust the far field reflector to shape the light spot to get the regular circular spot, and then to calculate the deviation of circular light spot center and the reference center, which is transformed to the steps of closed-loop control stepping motor , achieving high power lasers beam auto-alignment. the algorithm is used in a high power laser facility auto-alignment system, the results show that the far field pointing accuracy is better than 0.033″, which is better than the original system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1114002 (2017)
Suppression of Stress and Cracks in the Epitaxy of AlN by MOCVD Through a Hexagonal BN Nucleation Layer
WU Qing-qing, YAN Jian-chang, ZHANG Liang, CHEN Xiang, WEI Tong-bo, LI Yang, LIU Zhi-qiang, WEI Xue-cheng, WANG Jun-xi, and LI Jin-min
Monolayer hexagonal BN (hBN) material served as the nucleation layer in AlN epilayer by metal-organic chemical vapor deposition. Through this method both the stress and the cracks in AlN films were greatly suppressed. The monolayer hBN material was treated with artificial surface chemical modification to increase the dMonolayer hexagonal BN (hBN) material served as the nucleation layer in AlN epilayer by metal-organic chemical vapor deposition. Through this method both the stress and the cracks in AlN films were greatly suppressed. The monolayer hBN material was treated with artificial surface chemical modification to increase the defects in hBN and the nucleation sites for the subsequent AlN growth. We analyzed the quality of AlN materials with/without the hBN nucleation layer. The results show the hBN layer can help decrease the cracks, air voids and stress in AlN films. Meanwhile, the impacts of different V/III ratios on the surface morphology, the crystal quality and the stress in AlN films were studied. An optimized V/III-ratio range was obtained. Under the optimized growth condition, the stress in the AlN layer with the hBN nucleation layer can be eliminated completely, and the crystal quality of the AlN films with a hBN nucleation layer was comparable with that of AlN directly grown on sapphire..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1116001 (2017)
Effect of Substrate Temperature on the Properties of ITO Film and Black Silicon SIS Solar Cells
JIN Lei, LI Yu-fang, SHEN Hong-lie, TANG Qun-tao, JIANG Ye, ZHENG Chao-fan, YANG Nan-nan, and WANG Hong-mei
The cone nanostructures on n-silicon were fabricated by combination mask with reactive ion etching. After forming ultra-thin SiO2 on black silicon by wet oxidation method, the Indium Tin Oxide (ITO) film was deposited by magnetron sputtering equipment. Finally, the ITO/SiOx/n-Si solar cell was fabricated. The photoelecThe cone nanostructures on n-silicon were fabricated by combination mask with reactive ion etching. After forming ultra-thin SiO2 on black silicon by wet oxidation method, the Indium Tin Oxide (ITO) film was deposited by magnetron sputtering equipment. Finally, the ITO/SiOx/n-Si solar cell was fabricated. The photoelectric conversion efficiency of cells improved because of nanostructures, which can increase the absorption of light. Results showed that ITO deposited at different temperatures and presented the good optical and electrical properties. The ITO film grown at 250 ℃ exhibited the excellent optical and electrical properties. In 400~1 000 nm wavelength, the average transmittance of ITO up to 93.1%. By optimizing the H2O2 pretreatment time, the short circuit current of SIS solar cell increased from 26.84 mA/cm2 to 34.31 mA/cm2 due to the oxygen vacancy defects decrease in SiOx layers. When using H2O2 pretreated black silicon for 15 min and deposited ITO at 150 ℃, the SIS solar cell conversion efficiency reached 3.61%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1116002 (2017)
Optimization Algorithm of Static Tolerance in Focusing System Based on Linear Model
WANG Chuan-chuan, CEN Zhao-feng, LI Xiao-tong, LAN Shun, YANG Yao, and CHEN Hao
In order to assign the tolerances of focusing optical systems automatically, the tolerance allocation module is developed as a component of the optical simulation software OTS, and the tolerances of optical elements are optimized by this module. Based on the optical transmission matrix and the linear model of toleranceIn order to assign the tolerances of focusing optical systems automatically, the tolerance allocation module is developed as a component of the optical simulation software OTS, and the tolerances of optical elements are optimized by this module. Based on the optical transmission matrix and the linear model of tolerance, the merit function, tolerance allocation and feedback are explored. The reasonable tolerances are assigned by Monte Carlo method and other numerical techniques. An adaptive optimization algorithm is proposed and implemented in the software according to the sensitivity of every element, and verified by a multielement bi-pass experimental optical system. The advantage of the algorithm is shown in examples that the average number of iteration is decreased by 2 loops, and the total runtime is 40% less than Zemax with the similar results. This analysis is valuable for manufacturing and assembling optical systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1122001 (2017)
Research on the Stray Light Suppression for Super-resolution Optical System
PEI Lin-lin, XIANG-LI Bin, L Qun-bo, and SHAO Xiao-peng
In order to further improve the spatial resolution of the super-resolution satellite load optical system, it is necessary to suppress the stray light of the system to obtain accurate original images. By ray tracing, the stray light is analyzed, and the source of stray light is confirmed. Through the quantitative analysIn order to further improve the spatial resolution of the super-resolution satellite load optical system, it is necessary to suppress the stray light of the system to obtain accurate original images. By ray tracing, the stray light is analyzed, and the source of stray light is confirmed. Through the quantitative analysis and structural finite element analysis by Traccpro, the size of the hood and the position of the block were optimized, the point sources transmittance of the external point of the optical system is 10-3. The stray light suppression scheme is effective. The stray light suppression measures proposed in this paper provide theoretical support for the engineering application of Cassegrain optical system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1122002 (2017)
Design Method for the Near-field Diffractive Optical Elements with Large Diffraction Angle Based on the Rayleigh-Sommerfeld Diffraction Theory
LI Jing, WU Peng, YANG Zheng, ZHENG Qian-ying, LI Tao-jie, XIANG Yang, DU Chun-lei, and YIN Shao-yun
A novel method is presented for designing the near-field diffraction optical element (DOE) with large diffraction angle based on the Rayleigh-Sommerfeld diffraction theory. The relation of space position of sampling points between the DOE surface and the receiving surface is studied. The forward and inverse diffractionA novel method is presented for designing the near-field diffraction optical element (DOE) with large diffraction angle based on the Rayleigh-Sommerfeld diffraction theory. The relation of space position of sampling points between the DOE surface and the receiving surface is studied. The forward and inverse diffraction calculation methods without far-field and paraxial approximation are used. The design method of near-field DOE with large diffraction is obtained by modifying the traditional Gerchberg-Saxton algorithm. Compared with the traditional design method and the existing large diffraction angle design method, the proposed method shows significant advantages on designing the same "田" Shape target pattern. The simulation results show that the target pattern in the near field with large diffraction angle is accurately reconstructed by using the proposed method, while the reconstructed light fields with the other two methods shows dramatical distortion or fuzziness..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1122003 (2017)
Designfor Cooled Dual-band Infrared Refractive-Diffractive Hybrid Optical System of Athermalization and Wide FOV
TAO Zhi, WANG Min, XIAO Wei-jun, and GUO Wang-kai
On the basis of the dual-band athermal theory, a cooled dual-band infrared refractive-diffractive hybrid optical system of athermalized and wide field of view was designed. The system consists of 4 lenses and introduces only 1 diffractive surface and 1 aspherical surface, the full field of view is 80.2°, the focalOn the basis of the dual-band athermal theory, a cooled dual-band infrared refractive-diffractive hybrid optical system of athermalized and wide field of view was designed. The system consists of 4 lenses and introduces only 1 diffractive surface and 1 aspherical surface, the full field of view is 80.2°, the focal length is 8 mm, F number is 2, the operating wavelength range is 3.5~4.8μｍ and 8~12μｍ, and the cold stop efficiency is 100%. The solutions of 4 separate thin lenses were obtained by analyzing dual-band achromatic and athermalized theory. Further, establishing the material model of athermalized dual-band optic system and choosing the optical materials properly. According to requirements, the dual-band athermal optical system with temperature of －40℃ to 60℃ was designed with the use of optical passive. The reasults prove that the optical system obtains a good image quality during －40℃ to 60℃, and realizes athermalization..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1122004 (2017)
Research on Ladder-type Compensation Filter Based on Solar Simulator
FU Xiu-hua, YANG Jin-ye, LIU Dong-mei, ZHANG Jing, and GUO Kai
The solar simulator is a device that uses artificial light to simulate sunlight, as an important component of the solar simulator, the accuracy of the filter spectral requirements are getting higher and higher. In this paper, a step compensation filter with five different spectral requirements in the 0.4~1.1 μm band isThe solar simulator is a device that uses artificial light to simulate sunlight, as an important component of the solar simulator, the accuracy of the filter spectral requirements are getting higher and higher. In this paper, a step compensation filter with five different spectral requirements in the 0.4~1.1 μm band is designed by establishing a mathematical model and introducing a new evaluation function. In the process of film preparation, the least squares method was used to fit the experimental data, and the relationship between the residual deposition amount and the thickness of the film was found, which solves the spectral effect of the residual deposition on the film, and the film finally meets the requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1123001 (2017)
Mode Multiplexer and Demultiplexer Utilizing Tapered Couplers
YANG Tian-jun, LI Shi-qi, WANG Peng-jun, and CHEN Wei-wei
In this paper, we design and demonstrate a mode (de)multiplexer using tapered couplers on a silicon-on-insulator substrate by commercial 0.18 μm complementary metal-oxide-semiconductor compatible processes. By controlling the width of a tapered waveguide, the mutual conversion between the fundamental mode in the tapereIn this paper, we design and demonstrate a mode (de)multiplexer using tapered couplers on a silicon-on-insulator substrate by commercial 0.18 μm complementary metal-oxide-semiconductor compatible processes. By controlling the width of a tapered waveguide, the mutual conversion between the fundamental mode in the tapered waveguide and the high-order mode in the multimode straight waveguide can be realized due to the matching of modal effective indexes. For the multiplexing and demultiplexing of the TE0, TE1 and TE2 modes, the fabricated device, which is composed of a mode multiplexer, a multimode straight waveguide, and a mode demultiplexer, exhibits crosstalk lower than -8.05 dB within a bandwidth from 1 530 nm to 1 570 nm. The crosstalk is less than -16.43 dB for the multiplexing and demultiplexing of the TE0 and TE2 modes..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1123002 (2017)
Design and Fabrication of Rigid Fresnel Prisms for Complex Treatment of Strabismus in Children
FU Ming-lei, HU Wei-jie, LE Zi-chun, Manko D.Y., Antonov E.E., Kryuchyn A.A., and Petrov V.V.
In this paper, we present our design of a rigid Fresnel prism and derive the calculations of its transmittance and distortion. The transmittance of prisms made of different kinds of polymers and their distortion were numerically simulated. Simulation results showed that polymethyl methacrylate (PMMA) had a larger Abbe In this paper, we present our design of a rigid Fresnel prism and derive the calculations of its transmittance and distortion. The transmittance of prisms made of different kinds of polymers and their distortion were numerically simulated. Simulation results showed that polymethyl methacrylate (PMMA) had a larger Abbe coefficient and a lower material absorption rate than polyvinyl chloride (PVC). Then, on the basis of the simulation, stamps for the prisms were machined using the diamond-cutting method; the surface roughness of the stamps reached class 14. We verified that low-cost prisms can be fabricated from PMMA using the thermopressing method under the conditions of 180 ℃ and 130 kg/cm2. A system was constructed to test the prism diopter (PD) values of the samples. Experimental results showed that the deviations between the calculated and actual PD values for 10Δ (low PD), 20Δ (medium PD), and 30Δ (high PD) prisms were 0.01Δ, 0.04Δ, and 0.02Δ, respectively. The PD deviations of the sample prisms all agreed with the Chinese tolerance standard for a medical prism. Hence, we verified that the rigid prisms fabricated in this study are sufficiently precise to reflect light and are a high-quality, low-cost solution for the treatment of strabismus in children..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1123003 (2017)
High Repetition Frequency Characteristics of Image Intensifier in High-speed Imaging Application
LIU Lu, GUO Ming-an, YAN Ming, LI Gang, YANG Shao-hua, SONG Yan, and GAO Shuai
To solve these gray reversal and embossing effect problems, an imaging experiment platform for studying high repetition frequency character of image intensifier was set up. Experimental research was made on the relationship between the double-frame imaging and system parameter like exposure time and delay time. ExperimTo solve these gray reversal and embossing effect problems, an imaging experiment platform for studying high repetition frequency character of image intensifier was set up. Experimental research was made on the relationship between the double-frame imaging and system parameter like exposure time and delay time. Experimental results show that the problems of the second frame were caused by the saturation of the first frame, and the generation principle of gray reversal and embossing effect was analyzed. By increasing the gain of AD sampling the gray reversal and embossing effect problems were solved. The results of this paper provide theoretical and experimental basis for the imaging application of image intensifier at high repetition frequency..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1123004 (2017)
Monte-Carlo Simulation of Output Electron Cloud from a Microchannel Plate in a Saturation Mode
XIE Yun-tao, ZHANG Yu-jun, and SUN Xiao-quan
The performance of microchannel plate (MCP) detectors, including the temporal and spatial resolutions, varies significantly for MCPs work in a saturated mode due to high intensity illumination. In this paper, the influence of positive charges which accumulate on inner channel wall was added to a electron cloud motion mThe performance of microchannel plate (MCP) detectors, including the temporal and spatial resolutions, varies significantly for MCPs work in a saturated mode due to high intensity illumination. In this paper, the influence of positive charges which accumulate on inner channel wall was added to a electron cloud motion model. It is the main difference between the MCP model in a saturated and a non-saturated mode. The kinetic characteristics of the electron clouds were calculated and analyzed. Simulation results show that the Energy Distributions Of Electrons (EDOEs), in a saturated mode, have a similar shape for MCPs with different electrode penetrate depth. This is very different from the results obtained in a non-saturated case. It is concluded that these phenomena come from the accumulation of positive charges near the exit of the channel. The EDOEs fit well with the experimental data of related literature, which verifies the correctness of this model..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1125001 (2017)
Sagnac-loop-based Optical Coding for All-optical Analog-to-digital Conversion Employing Soliton Self-frequency Shift
WANG Shu-bing, ZHANG Zhi-yao, PENG Di, ZHANG Xu-yan, and LIU Yong
A novel optical coding scheme employing parallel Sagnac-loops is proposed for all-optical analog-to-digital converters based on soliton self-frequency shift effect. The proposed coding scheme is numerically demonstrated in a 5-bit SSFS-based all-optical ADC with a wavelength range of 1 601 nm to 1 707 nm, where the resA novel optical coding scheme employing parallel Sagnac-loops is proposed for all-optical analog-to-digital converters based on soliton self-frequency shift effect. The proposed coding scheme is numerically demonstrated in a 5-bit SSFS-based all-optical ADC with a wavelength range of 1 601 nm to 1 707 nm, where the results show that the maximum differential nonlinearity error and the integral nonlinearity error are 0.088 and 0.482 Least Significant Bit (LSB), respectively. Compared with other wavelength coding counterparts, the proposed optical coding scheme has a simple architecture and a broad operation wavelength range, and is easy to achieve a larger coding bit..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1125002 (2017)
Oxide-Aperture Dependent-RIN Research of High-speed, Energy-Efficient 980 nm VCSELs
LI Hui, JIA XIAO-wei, and WEI Ze-kun
Oxide-aperature-diameter dependent analysis of RIN for high-speed, energy-efficient Vertical-Cavity Surface Emitting Lasers (VCSELs) have been performed. Small oxide-aperture diameter VCSELs are prefered for low energy consumption data transmission. We demonstrate that energy efficiency is not in conflict with our VCSEOxide-aperature-diameter dependent analysis of RIN for high-speed, energy-efficient Vertical-Cavity Surface Emitting Lasers (VCSELs) have been performed. Small oxide-aperture diameter VCSELs are prefered for low energy consumption data transmission. We demonstrate that energy efficiency is not in conflict with our VCSELs′ RIN characteristics. The experimental results indicate that small oxide-aperture diameter VCSELs, which are the most suitable for energy-efficient, temperature-stable operation, exhibit lower laser RIN due to less mode competition inside the smaller optical cavity volume. Our energy-efficient VCSELs fulfill the RIN requirements of the 32G Fibre Channel standard. These devices are advantageous for future high performance computer applications..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1125003 (2017)
Modelingand Analysis of a Uni-traveling Carrier Phototransistor Based on its Small Signal Equivalent Circuit
SUN Dan, XIE Hong-yun, LIU Rui, LIU Shuo, WU Jia-hui, and ZHANG Wan-rong
The small signal equivalent model of a Uni-Traveling Carrier Double Hetero-junction Phototransistor (UTC-DHPT) was established. In this model, the optical generated current in UTC-HPT was introduced reasonably as part of base current. The influence of single carrier transportation in UTC-DHPT on photo transconductance,The small signal equivalent model of a Uni-Traveling Carrier Double Hetero-junction Phototransistor (UTC-DHPT) was established. In this model, the optical generated current in UTC-HPT was introduced reasonably as part of base current. The influence of single carrier transportation in UTC-DHPT on photo transconductance, emitter junction effective resistor, emitter junction capacitor, and collector junction capacitor were analyzed. Based on the established small signal equivalent model, the dependence of optical characteristic frequency and the optical generated current gain on optical window area and illumination light power of an InP-based UTC-DHPT were analyzed. At certain illumination light power, there is an optimum window area which can achieve the maximum optical characteristic frequency. Meanwhile, the optimum window area would change in certain range as illumination light power increasing. When chosen the optical injection window of 8×8 μm2, With the gradual increase of illumination light power, the characteristic frequency increases at first and then decreases, the highest value reaches 150 GHz at 280 μW. The gain of optical generated current increases gradually too and reaches the saturation gain of 82 dB under 750 μW..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1125004 (2017)
Research on the Detection Performance of Satellite Laser Ranging in Atmospheric Aerosol Based on the Slanting Transmission Model
CHEN Yu-feng, AN Ning, HAN Xing-wei, LIU Cheng-zhi, FAN Cun-bo, WEN Guan-yu, SONG Qing-li, and DONG Xue
Due to the uneven distribution of atmospheric aerosol, the detection performance of Satellite Laser Ranging in atmospheric aerosol is researched based on the Slanting Transmission Model of the laser transmitted in atmospheric aerosol. The distribution of aerosol is divided into horizontal and vertical directions. The vDue to the uneven distribution of atmospheric aerosol, the detection performance of Satellite Laser Ranging in atmospheric aerosol is researched based on the Slanting Transmission Model of the laser transmitted in atmospheric aerosol. The distribution of aerosol is divided into horizontal and vertical directions. The vertical direction is divided into infinite layers and the horizontal direction of each layer is regarded as the uniform distribution. Combining the scattering cross section and the scale distribution function of the aerosol particles, calculates the transmittance of the laser in each layer of aerosol, and integrals the atmospheric transmission of the laser finally. Compared with the empirical formula and Mie theory model, the transmittance value of laser in atmospheric aerosol calculated by Slanting Transmission Model is closer to the experimental value and the average of relative errors is only 3.5%, reducing by an order of magnitude, which indicates that the Slanting Transmission Model is suitable for calculating the relationship between the laser transmittance in aerosol, aerosol visibility, and telescope elevation. Combined with the lidar formula, the Slanting Transmission Model is used to simulate the satellite detection probability of different orbital in aerosol, the results demonstrate that the detection probability of MEO and LEO satellites are more than 40%, but the GEO satellites is only 15%. And the Satellite Laser Ranging in light haze can be realized by the detector with high detection efficiency and the laser with high power. The results can give a reasonable interpretation for the previous experiment reports and show a certain reference value to the upgrading of SLR system in the future..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1128001 (2017)
Rapid Method to Measure Turbine Blade Based on Laser Sensor
LI Bing, YAN Xiao, CHEN Lei, XIN Mei-ting, and WEI Xiang
A novel method was proposed based on laser line-scanning sensor to obtain point clouds of turbine blade. Due to the geometrical invariability, the standard sphere was used as measuring basis. The surface data of blades were measured by four-coordinate measuring machine with line-scanning laser sensor, which can ensure A novel method was proposed based on laser line-scanning sensor to obtain point clouds of turbine blade. Due to the geometrical invariability, the standard sphere was used as measuring basis. The surface data of blades were measured by four-coordinate measuring machine with line-scanning laser sensor, which can ensure the measuring efficiency of blades and take the control accuracy of the measuring machine into account. Firstly, the point cloud data of the turbine blade were obtained. Then some pre-processing operations, such as error compensation, de-noising and data reduction, were performed before the matching operations. Finally, the Non-Uniform Rational B-Splines curve fitting algorithm was utilized to get the characteristic curve of blade surface. The experimental results indicated that the method can effectively improve the reconstruction accuracy of the blade leading and trailing edge and provide more accurate raw data for the 3D modeling of the blade..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1128002 (2017)
Highly-Accuract Mid-Infrared Atmospheric Methane Sensor System
YE Wei-lin, HE Xun, MENG Yong-xian, ZHENG Zhi-dan, and ZHENG Chuan-tao
A highly-accurate atmospheric CH4 sensor system using mid-infrared room-temperature Continuous-Wave (CW) Interband Cascade Laser (ICL) was reported. The emitting wavenumber range of the ICL is from 2 998.4 to 2 999.6 cm-1, which covers a strong CH4 absorption line at 2 999.06 cm-1. In order to enhance CH4 absorption, aA highly-accurate atmospheric CH4 sensor system using mid-infrared room-temperature Continuous-Wave (CW) Interband Cascade Laser (ICL) was reported. The emitting wavenumber range of the ICL is from 2 998.4 to 2 999.6 cm-1, which covers a strong CH4 absorption line at 2 999.06 cm-1. In order to enhance CH4 absorption, a multi-pass gas cell with a volume of 220 mL, optical path length of 54.6 m was employed. A LabVIEW platform as well as a Data Acquisition Card (DAQ) was used to generate the scan and modulation signal of the ICL and extract the second harmonic signal from the detector output signal. Experimental results showed that when the averaging sampling time was 3.3 s, the Allan deviation of the sensor system was 11.2 ppbv. This sensor system was used to measure the atmospheric CH4 inside and outside the laboratory for a long time, and it is proved to be of great practical value in engineering..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1128003 (2017)
Reaserch of a Microscopic Spectral Imaging System with Multi-band Illuminants
LIAO Cheng-sheng, ZENG Li-bo, and WU Qiong-shui
Compound staining method can solve the problem that traditional combination screening of cervical cancer can not be carried out on the same smear. In view of the problems of DNA absorbance interference and color restoration distortion caused by compound staining, a microscopic spectral imaging system with multi-band ilCompound staining method can solve the problem that traditional combination screening of cervical cancer can not be carried out on the same smear. In view of the problems of DNA absorbance interference and color restoration distortion caused by compound staining, a microscopic spectral imaging system with multi-band illuminants was established in this paper. The design of composite illuminants gave consideration to both the restoration of color image and the establishment of absorbance model, multi-spectral unmixing model were constructed by multiple linear regression method, and by using this modle Feulgen′s real absorbance were unmixed from the mixing muti-spectral images for DNA quantitative analysis , and pseudo color images were also composed to meet the doctors′ requirements and habits at the same time. Experimental results show that: the Full Width at Half Maximum (FWHM) of the chosed four-band illuminants were 12 nm/12 nm/14 nm/19 nm, and they were satisfactory narrowband monochromatic lights; The measured maximum offset of spot does not exceed 3 scale by using a microscope micrometer as a ruler and the original illuminant as a standard, so parallelism and coaxiality of the composite illuminants met the requirements of imaging system; The synthesis pseudo color images were bright and full , and have clean background, they will not cause interference and obstacles to doctor′s diagnosis.The absorbance unmixing model can successfully unmixing the real absorbance of feulgen and accurately calculate the content of DNA: The liver smear of mice was used as the measuring specimen and the calculated DNA index (DI) values accorded with the polyploidy of liver cells; In contrast experiments using a cervical positive sample, the DI values of the diploid and tetraploid cells calculated by the two methods were almost equal, therefore, this method has higher accuracy and reliability..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1130001 (2017)
Classification of Trace Oil Pollutants in Water Quality
YUAN Yuan-yuan, WANG Shu-tao, KONG De-ming, and PAN Zhao
Based on strong fluorescence property of oil pollutant in water quality, a fluorescence detection system is constructed, gasoline, diesel, kerosene, engine oil with different concentrations in water quality are prepared to analyze their fluorescence characteristics. In order to identify the three oil with the similar fBased on strong fluorescence property of oil pollutant in water quality, a fluorescence detection system is constructed, gasoline, diesel, kerosene, engine oil with different concentrations in water quality are prepared to analyze their fluorescence characteristics. In order to identify the three oil with the similar fluorescence peaks, the Principal Component Analysis (PCA) combined with Extension Neural Network (ENN) is proposed, which can reduce input vector and identify similar substances. Compare with the ENN and PCA-BP, the results show that the proposed method can make the iteration number dropped from 265 to 60, make the sum of the squares of dispersion decrease from 0.236 5 to 0.014 5, make recognition efficiency increase from 72.50% to 96.25%, and reach the 10-6 level of recognition precision. The proposed method possesses high recognition accuracy and recognition efficiency, which can be used in spectral identification of other trace organic materials in water..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 46, Issue 11, 1130002 (2017)
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