Journals >Acta Photonica Sinica
Contents
2015
Volume: 44 Issue 7
26 Article(s)
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Research Article
Performance Analysis of Adaptive Optical System for Spatial Objectives
WEI Pei-feng, LU Zhen-wu, LIU Xin-yue, LIN Xu-dong, WANG Liang, DONG Lei, and JIA Jian-lu
The performance of adaptive optical system of a ground-based large telescope when observing spatial objectives degraded comparing with observing astronomical objectives . To adjust the parameters of adaptive optical system purposively, and get the best correction result, it was necessary to predict the performance of aThe performance of adaptive optical system of a ground-based large telescope when observing spatial objectives degraded comparing with observing astronomical objectives . To adjust the parameters of adaptive optical system purposively, and get the best correction result, it was necessary to predict the performance of adaptive optical system for spatial objectives. Presence of the best observation elevation range for spatial objectives having different orbits was validated by analysis of orbits based on the residual wavefront errors after correction. The corresponding calculation method was also concluded. The effects of the variation of atmospheric coherence length on the spatial fitting errors, Greenwood frequency on the temporal fitting errors, signal intensity on the wavefront measurement errors were analyzed based on the 1.23m telescope made by CIOMP. The result showed that the temporal fitting errors were primary compared to the spatial fitting errors, the wavefront measurement errors could be neglected when signal intensity of the spatial objectives varying, and the best observation elevations were different for different spatial objectives, orbits and telescope systems. An experiment system was constructed to test an adaptive optical system for different spatial objective by changing the aperture diameter of the turbulence phase plate, velocity and the light source intensity to simulate the variation of the atmospheric coherence length, Greenwood frequency and the signal intensity individually..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 701001 (2015)
Skylight Polarization Pattern-based Approach to the Location of the Sun and Solar Meridian
REN Jian-bin, LIU Jun, TANG Jun, WANG Chen-guang, WANG Fei, and ZHANG Nan
An approach to the location of the sun and meridian by means of the Rayleigh skylight polarization pattern was introduced, given that the polarized-light-aided navigation relys heavily on the position of some astronomical markers. Combining with the theoretical analysis based on the single Rayleigh scattering theory, tAn approach to the location of the sun and meridian by means of the Rayleigh skylight polarization pattern was introduced, given that the polarized-light-aided navigation relys heavily on the position of some astronomical markers. Combining with the theoretical analysis based on the single Rayleigh scattering theory, the skylight polarization pattern was practically detected the using the polarization analyzer. Then, with respect to the distribution stability of the polarization pattern, the information collected was clustered to locate the position of the sun with the polarization degree data, and that of the solar meridian with the E-vector data respectively. In this way, the location problem was changed to figure out the clustering center. Finally, the approach was tested through experiments on the theoretical and practical detected polarization pattern. Compared with the way of obtaining the solar location by the least square method, this approach can effectively take use of the stable distribution of the polarization pattern, locate the accurate position of astronomical marker based on the polarization information detected on a large scale, and skillfully process the captured data..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 701002 (2015)
Numerical Simulation for Wind Lidar Based on Optical Fiber Mach-Zehnder Interferometer
TAN Lin-qiu, HUA Deng-xin, WANG Li, HE Ting-yao, and CHANG Bo
An all-fiber incoherent wind lidar system was proposed and designed based on double-edge technique of optical fiber Mach-Zehnder interferometer. The algorithms for Doppler shift extraction and for wind velocity retrieval were theoretically analyzed. The optical fiber Mach-Zehnder interferometer used as a spectral analyAn all-fiber incoherent wind lidar system was proposed and designed based on double-edge technique of optical fiber Mach-Zehnder interferometer. The algorithms for Doppler shift extraction and for wind velocity retrieval were theoretically analyzed. The optical fiber Mach-Zehnder interferometer used as a spectral analyzer in the proposed system, was discussed to optimize for wind velocity measurement based on the signals backscattered by the molecules. Performances including wind measurement sensitivity, signal-to-noise ratio and measurement error of lidar system were numerically simulated based on the U.S. standard atmospheric model. For a ground-based molecular wind lidar at a wavelength of 532 nm, an error in the line-of-sight velocity component of the wind was found to be smaller than 1.4 m/s up to an altitude of 20 km, with the line-of-sight wind velocity within the range of ± 100 m/s, a 300-shot average and a vertical resolution of 1 000 m. Obtained results show that the designed system can be applied for long-distance and large-scale wind velocity measurement. The system will be able to provide a technical solution for the development of the compact Doppler lidar..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 701003 (2015)
Effect of Vibration and Far Field Turbulence on the Fine Tracking of Airborne Optical Ccommunication Terminal
LIU Yan-fei, DAI Yong-hong, ZHOU Hao-tian, SHAN Xin, and AI Yong
In order to reduce the volume and power consumption and improve the tracking accuracy, a small airborne fine tracking system with FPGA based on the characteristics of airborne platform vibration power spectral density was desighed and developed. To verify the fine tracking system ability, simulation tracking and disturIn order to reduce the volume and power consumption and improve the tracking accuracy, a small airborne fine tracking system with FPGA based on the characteristics of airborne platform vibration power spectral density was desighed and developed. To verify the fine tracking system ability, simulation tracking and disturbance rejection experiments, far-field beacon detection and communication experiments were carried out, the airborne platform vibration suppressed effect and turbulence impact on fine tracking in various intensity were analyzed. In 3.4km far-field atmospheric turbulence experiment, a aircraft to ground communication through angular velocity was simulated.Simulation distance was about 20~30 km and flight speed was about 700 ~ 900 km/h. The experimental results show that, the fine tracking system has strong rejection effect on airborne platform vibration, the tracking accuracy is about 3 μrad. The receiving signal power can be improved 4~5.9 dB in simulated aircraft to ground communication experiment. The fine tracking system has the characteristics of flexibility and high accuracy..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 706001 (2015)
Embedded Strain Homogenized FBG Sensor for Smart Cables
WU Jun, CHEN Wei-min, SHU Yue-jie, LIU Li-hua, and ZHAO Xia
The overall non-uniform gratings were simplified cascading multiple uniform sub-gratings, the effects of three typical non-exponential decays on the output spectrum of Fiber Bragg Grattings(FBGs) were simulated. Simulation results show that the conventional FBG strain sensor is not suitable for anchor axial strain measThe overall non-uniform gratings were simplified cascading multiple uniform sub-gratings, the effects of three typical non-exponential decays on the output spectrum of Fiber Bragg Grattings(FBGs) were simulated. Simulation results show that the conventional FBG strain sensor is not suitable for anchor axial strain measurement. The structure of FBG strain sensors packaged in thin-walled capillaries was proposed, and the measurement principle and mechanical characteristics were analyzed, the basic formula of capillary material and thickness selection was deduced. The sensor samples were developed with carbon fiber composite materials, and the mechanical tests were carried out. The test results show that the sensors′ performance expectations are achieved. Two FBG strain sensors were pre-implanted into the test anchor, during the tensile process. FBG spectrum occurs no broadening, fission sign, which can meet all the requirements of the prototype cable tests. The relationship between FBG outputs and cable tension are of good consistency, and are of good reproducibility and linearity, which proves that the tension measurement method is entirely feasible.Key words:.
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 706002 (2015)
9.2 GHz Microwave Frequency Transmission via 50 km Optical Fiber
MENG Sen, GUO Wen-ge, ZHAO Wen-yu, YAN Lu-lu, ZHANG Xuan, JIANG Hai-feng, and ZHANG Shou-gang
Based on the method of phase conjugation stabilization, a real-time noise cancellation system was proposed. The system which is a modular structure, is composed of microwave reference signal generating, phase compensation and optical fiber transmission module. The experimental results of our ultra-stable 9.2 GHz frequeBased on the method of phase conjugation stabilization, a real-time noise cancellation system was proposed. The system which is a modular structure, is composed of microwave reference signal generating, phase compensation and optical fiber transmission module. The experimental results of our ultra-stable 9.2 GHz frequency transfer via a 50 km fiber spool were shown. In 9 days laboratry measurement, the system exhibits frequency transfer stabilities (standard Allan deviation) of 4.2E－13@1s/4.3E－14@1day for freE－running and 5.8E－14@1s/1.9E－17@1day for noisE－compensated link. This system match the requirement of 100 km scale frequency transfer of ultra-stable microwave atomic clocks..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 706003 (2015)
Fast Visual Tracking with Spatial Phase Correlation
ZHA Yu-fei, ZHANG Li-chao, QIN Bing, and HUANG Hong-tu
The visual tracking based on phase correlation is always failure, because the response is dirac delta function disturbed by the noise and cluster. The desired correlated output distribution is adopted in average of synthetic exact filters, which obtains the excellent filtered result. This paper designs the response relThe visual tracking based on phase correlation is always failure, because the response is dirac delta function disturbed by the noise and cluster. The desired correlated output distribution is adopted in average of synthetic exact filters, which obtains the excellent filtered result. This paper designs the response related with the object′s spatial position to replace the dirac delta function, which can achieve a robust filter. In order to adapt the changed object, peak-to-sidelobe ration was used to evaluate the results to update the filter. The fast Fourier transform was used to accelerate the algorithm to track the object fast and robustly. The experiments show that the proposed method can process 50 frames per second, and excels the state-of-the-art methods in both accuracy and precision..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 710001 (2015)
Optical Color Image Encryption in Diffraction Imaging Scheme Based on Spectrum Fusion
LI Jing, LV Xiao-dong, MA Mao-fen, and QIN Yi
A method for color image encryption was proposed. For encryption, a color image is separated into three components which are red, green and blue. The three grey images are transformed with Discrete Cosine Transform (DCT). Then these DCT spectrums are partially retained and merged into a single real value matrix, namelyA method for color image encryption was proposed. For encryption, a color image is separated into three components which are red, green and blue. The three grey images are transformed with Discrete Cosine Transform (DCT). Then these DCT spectrums are partially retained and merged into a single real value matrix, namely the composite spectrum. Thereafter, the matrix is encrypted by the diffractive-imaging schemes. The decryption is the inverse of the encryption. Since a special domain has been set in the composite spectrum, the algorithm for retrieving the composite spectrum has overcome the stagnation problem and converges quickly. Computer simulations show that a color image can be successfully encrypted into a single noise-like intensity pattern, and the decrypted image can be obtained with high quality..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 710002 (2015)
Calibration and Characterization of an AOTF-based Hyperspectral Imaging System
GAO Zhi-fan, ZHANG Hong-ping, WU Qiong-shui, and ZENG Li-bo
A systemic calibration and a characterization approach were presented for acousto optic tunable filter based hyperspectral imaging system. A series of tests were conducted to validate the performance of a self-integrated hyperspectral imaging system. Results show that the presented approach effectively validate the sysA systemic calibration and a characterization approach were presented for acousto optic tunable filter based hyperspectral imaging system. A series of tests were conducted to validate the performance of a self-integrated hyperspectral imaging system. Results show that the presented approach effectively validate the systematic characteristics in both spectral and spatial domains. Through flat-fielding correction, the system responsivity non-uniformity, known as pattern noise, is apparently eliminated. The spectral sensitivity of the system is corrected by controlling both the camera exposure time and digital gains at each wavelength, which significantly improve the signal to noise ratio of the system. By studying the system outputs with different camera exposure time, instead of using an attenuator to adjust the input light intensity, a more efficient and cost effective approach to measure the spectral linearity of the system is presented. The proposed methods are also applicable to the liquid crystal tunable filter based hyperspectral imaging systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 711001 (2015)
Microscopy Imaging Definition Criterion Using Visual Attention Mechanism and Edge Spreading Evaluation
ZHAO Ju-feng, MAO Lei, LIU Cheng, and FENG Hua-jun
To achieve the consistency with subjective evaluation, the paper proposes a microscopy image sharpness metric using visual attention mechanism and edge spreading measurement. According to the gray difference of pixels at different spatial location, visual attention index map is calculated to simulate the way of human vTo achieve the consistency with subjective evaluation, the paper proposes a microscopy image sharpness metric using visual attention mechanism and edge spreading measurement. According to the gray difference of pixels at different spatial location, visual attention index map is calculated to simulate the way of human vision system observing the features of scenery. By this way, weight is given for different regions and pixels, and the potential focuing areas is extract by segmentation. Using edge spreading evaluation in this areas, an average edge spreading of horizontal and vertical direction is obtained, which is considered as the last sharpness metric. The authors design experiments for subjective assessment and objective evaluation. The experiment and comparison demonstrate that, the proposed method can effectively solve the key problems in the evaluation of microscopy image, and satisfy the consistency of objective and subjective evaluation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 711002 (2015)
Optical System Design of LCTF-Based Airborne High Spectral Resolution Camera
WANG Wei, and SHEN Zhi-xue
Considering that the space and weight of unmanned airborne equipment is limited, an unmanned airborne high spectral imaging optical system on the basis of liquid-crystal tunable filter liquid crystal tunable filter, which has 46 channels. The working spectrum of the system covers the visible light to near-infrared lighConsidering that the space and weight of unmanned airborne equipment is limited, an unmanned airborne high spectral imaging optical system on the basis of liquid-crystal tunable filter liquid crystal tunable filter, which has 46 channels. The working spectrum of the system covers the visible light to near-infrared light (0.45 ~0.9 μm), the spectrum resolution is 10 nm, the focal length is 81.25 mm, relative aperture is 1/2.5, the full viewing field angle is 12°, the maximum distortion is less than 0.12%, the ground pixel resolution is 0.4 m, the ground breadth is 1 km×0.87 km with 5000m of flight level. The liquid crystal tunable filter overall embedded design is adopted and the aberration produced by liquid crystal tunable filter is revised. The imaging quality of the system is excellent under the no vignetting design condition, the root-mean -square diameter of maximum dispersed spot is less than 5 μm, the modulation transfer function of every viewing field is more than 0.54 under the sCMOS Nyquist frequency situation. Zemax multi-configuration and thermal analysis were used to simulate the imaging quality of system. 25℃±5℃ of system temperature control scheme and 35℃±1℃ of liquid crystal tunable filter temperature control scheme was confirmed. In the range of 3 km~6 km aviation altitude, the system doesn′t need image motion compensation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 711003 (2015)
Optical Microscopic Imaging and Image Processing for Cell Factories
JI Xiao-qiang, CHENG Jie-zhang, LI Qi, GONG Ping, GUO Rui-juan, and YU Yuan-hua
A simple structure, clear imaging optical microscopic imaging system aiming at the requirement of long working distance and large tilt angle for the cell factories was designed. According to the characteristics of the cell images uneven illumination, sample turbidity, cell adhesion, cell overlap and the unobvious cell A simple structure, clear imaging optical microscopic imaging system aiming at the requirement of long working distance and large tilt angle for the cell factories was designed. According to the characteristics of the cell images uneven illumination, sample turbidity, cell adhesion, cell overlap and the unobvious cell distance, the Retinex algorithm was adopt to pretreat the image, then a fast and compositive image segmentation algorithm based on the Otsu and K-means clustering was used to segmented the cell images, at last, an improved fast connected component labeling method and a rapid high precision cell counting method were applied to count the number of cells. The results of simulation experiment and actual test show that the imaging quality of the system achieved the project actual requirements for resolution and definition, and the morphological and distribution of cells in culture dish could be identified clearly. The cell microscopic image processing method has a good image enhancement effect, weakens the phenomenon caused by the uneven illumination and sample turbidity that human vision cannot clearly distinguish the cell, and eliminates the statistical error caused by that image segmentation is not in place. The cell counting accuracy is above 95%. The method is suitable for various cells, which can meet the requirements of real-time and off-line monitoring for cell factories..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 711004 (2015)
Attitude Measurement of Spatial Moving Object Based on Vectors of Light Beams
HUO Ju, YANG Ning, and YANG Ming
In order to achieve the high precision measurement for the attitude of spatial moving object, a measuring system based on the vectors of light beams is presented. In this system, light beams are mounted on the moving object as the cooperation target, and their projective spots on the reception planes are recorded by hiIn order to achieve the high precision measurement for the attitude of spatial moving object, a measuring system based on the vectors of light beams is presented. In this system, light beams are mounted on the moving object as the cooperation target, and their projective spots on the reception planes are recorded by high speed cameras. To achieve the accurate calibration of the high speed camera, flexible calibration target is constructed with 9 original feature points on the reception plane based on planar homography. According to the calibration results, the vectors of light beams in world coordinate system are acquired, while the corresponding vectors in object coordinate system can be obtained by their installation sites on the object. Then the attitude parameters of the moving object are calculated with the vectors of light beams in world coordinate system and object coordinate system. The experiments results show that the measuring errors of the attitude parameters are within 1′(1σ). As a result, the system in this paper can realize the high precision measurement for the attitude of spatial moving object..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 712001 (2015)
Design and Deformation Analysis of the Filter-array in the Filter-array Multi-spectral Camera
FANG Yu, LV Qun-bo, LIU Yang-yang, TAN Zheng, LI Wei-yan, PEI Lin-lin, and WANG Jian-wei
In order to limit the size of aliasing area caused by distance between filter-array and the detector and improve efficiency of pixel utilization, the filter-array was designed. Filter-array which is diferent from itself in-orbit state is withstanded greater differential pressure in the ground testing experiment, the suIn order to limit the size of aliasing area caused by distance between filter-array and the detector and improve efficiency of pixel utilization, the filter-array was designed. Filter-array which is diferent from itself in-orbit state is withstanded greater differential pressure in the ground testing experiment, the surface of filter-array changed, which may adversely affect the quality of multi-spectral imaging camera. Baesd on Finite element method , the deformation of the filter-array was analyzed which is attached to original surface of filter-array in Zemax by means of Zernike polynomials. The changes of the modulation transfer function of multi-spectral imaging camera was studied. The results show that under pressure difference, The modulation transfer function of system is not changed significantly and the impact of filter-array′s deformationon on imaging quality of optical system can be negligible..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 712002 (2015)
Position Error Analysis in Radius Interferometric Measurements
MAO Jie, HOU Xi, and WU Fan
In order to improve the position precision, a single analytical expression for position errors was presented in terms of the various error contributors, including phase measuring interferometer errors, wavefront errors of transmission sphere, surface deviation and adjustment errors. The contrastive experiments indicateIn order to improve the position precision, a single analytical expression for position errors was presented in terms of the various error contributors, including phase measuring interferometer errors, wavefront errors of transmission sphere, surface deviation and adjustment errors. The contrastive experiments indicate that after controlling the adjustment errors, the linear trend of power and radius is changed to the random trend, and the radius variation is decreased from 7.05 μm to 0.5 μm. The adjustment errors are the main error contributors. The power can be effectively controled by minishing adjustment errors. Thus the interferometric radius precision is improved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 712003 (2015)
Design of Automatic Aiming System of the Luminance Thermometer
CHENG Peng-fei, CAO Li-fang, HOU Pei-guo, YANG Zhe, and WANG Yu-tian
Manual calibration is often used in the luminance thermometer, which exists a high influential artificial factor and a low repeat ability of calibration. In order to make the thermometer accurately and automatically aim at the aiming point of the lamp, double degree of freedom automatic aiming system is designed. The YManual calibration is often used in the luminance thermometer, which exists a high influential artificial factor and a low repeat ability of calibration. In order to make the thermometer accurately and automatically aim at the aiming point of the lamp, double degree of freedom automatic aiming system is designed. The YG-QP36 four quadrants detector was chosen as the photoelectric detector. The mechanical structure of automatic aiming system is designed, and the stepper motor has the characteristic of self-locking and two-way accurate location, which can scan the aiming point of the lamp in two degree of freedom. The optical fiber can isolate electronic components from high temperature environment, which reduces the temperature influence on electronic components. The temperature-voltage data was collected in 800~1 200℃, and the data was fitted with the least squares support vector machine. The relative error is less than 0.05%, the reconstruction of mean square error is 0.019 6. The least squares fitting between the distance of the flare of the circle to the origin of coordinates and voltage was made. The spot diameter was measured, experiment results show that the double degree of freedom automatic aiming system can improve the accuracy of calibration, and reduce the repeated calibration error..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 712004 (2015)
Power-spectrum-based Method of Identifying Rotational Direction in Remote Angular-velocity Measurement with Spatial Filtering Technique
ZHU Zhi-xiong, ZENG Xiang-kai, LIU Quan-shun, and CHEN Yang
In order to exactly identify the rotational direction of the measured body in the remote angular-velocity measurement with spatial filtering technique, an approach to estimating the rotational direction was proposed based on the analysis of power spectrum density. In the identification method of rotational direction, tIn order to exactly identify the rotational direction of the measured body in the remote angular-velocity measurement with spatial filtering technique, an approach to estimating the rotational direction was proposed based on the analysis of power spectrum density. In the identification method of rotational direction, two identical photovoltaic-cell arrays with the duty ratio of 0.5 are arranged each other with the shift of a half spatial period, which leads to a differential spatial filter. Two parallel differential spatial filters are placed in a certain interval, and then construct a sensor with double differential spatial filters. The power spectrum densities of the two output signals from one differential spatial filter are conjugated each other, thus the direction coefficients D1 and D2 of the linear velocities on two differential spatial filters are calculated with four output signals of the sensor, and the signs of D1 and D2 represent the moving directions of the measured-body image on the differential spatial filters. The rotational direction and center of the measured-body image can be determined by the signs of D1 and D2, together with the relation between the central frequencies f1 and f2 of two output signals from the differential spatial filters. D1>0 and D2<0 represent the clockwise rotation, and D1<0 and D2>0 represent the counter-clockwise one. For other cases as D1D2>0, the rotational directions can be decided by the sign of D1 and the relative relation between f1 and f2. The proposed method can effectively identify the rotational direction in the remote angular-velocity measurement with spatial filtering technique, which has the features as being single and easy to operate, and having strong adaptability..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 712005 (2015)
Fabrication of Organic/Inorganic Thermo-Optical Switch and Development of Its Measurement System
LUO Qian-qian, ZHENG Chuan-tao, HUANG Xiao-liang, WANG Xi-bin, ZHANG Da-ming, and WANG Yi-ding
A 1×2 multimode interference Mach-Zehnder interferometer thermo-optical switch was designed by combining the advantages of organic polymer and inorganic SiO2 materials. The structural parameters were optimized and the device performances were simulated. Fabrication techniques, such as chemical vapor deposition andA 1×2 multimode interference Mach-Zehnder interferometer thermo-optical switch was designed by combining the advantages of organic polymer and inorganic SiO2 materials. The structural parameters were optimized and the device performances were simulated. Fabrication techniques, such as chemical vapor deposition and lithography, were adopted to fabricate the switch, and the waveguide appearance were characterized. Furthermore, in order to measure the performance of the device, a kind of measurement system for optical switch was developed using ARM7 processor and InGaAs photoelectric detector. The system is mainly composed of low-ripple linear power, photoelectric detector, preamplifier, main amplifier, signal regulator, AD converter, main controller, display module, etc. The system was calibrated with the help of a commerical optical power meter, and its zero drift is found to be smaller than 0.5 dBm. Applying different driving voltages on the electrode, the output optical power from one port of the switch was both measured by the self-developed optical power meter and the commerical power meter. the experimental results show that, the obtained two curves have the same variation trend, and when the driving voltage is 10 V, the two measured output powers both become the smallest. This shows that the measurement system has good performance and can meet the needs of the actual measurement. The system provides a solution for the performance measurement of optical switch due to its small size and high performance-cost ratio..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 713001 (2015)
Research on Polarization Dependent Loss of Micro Ring Resonator Based Optical Switches
ZHANG Zhong-yi, WU Bao-jian, WEN Feng, LIAO Ming-le, and QIU Kun
A design method of micro-ring resonator based optical switches capable of simultaneously providing the transmission of transverse electric and transverse magnetic modes was presented, which can be applied to the buildup of polarization-independent switch chips operating in a given wavelength plane. In order to realize A design method of micro-ring resonator based optical switches capable of simultaneously providing the transmission of transverse electric and transverse magnetic modes was presented, which can be applied to the buildup of polarization-independent switch chips operating in a given wavelength plane. In order to realize polarization-independent transmission, transverse electric mode and transverse magnetic mode should both work at the same resonant peak and the group refractive index of these two modes are equal to each other in this resonant wavelength. The silicon-on-insulator based micro-ring parameters were optimized with MODE Solutions, the chip simulation model was then set up by Interconnect to investigate transmission and transfer characteristics of the optical switch chip. By optimum design, the resulting micro-ring resonator based optical switching chip had a very low polarization dependent loss of 0.13 dB, while the transmission delay was 42.5 ps. Simulation shows that the length variation of the micro-ring resonator should be smaller than about 10nm for the polarization dependent loss of 1 dB, in which the thermo-optic effect can be used to compensate for the fabrication error with the perimeter change of 2.2 nm/K..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 713002 (2015)
Characteristic Analysis of Single and Double Micro Ring Resonant Cavity Used in Mach-Zehnder Interferometer Filter
YAN Chong-yu, GAO Shao-hong, SONG Dong-yu, AN Li-min, LIU Jian-bo, XIAO De-hang, and ZHANG Zi-xin
The single microring resonator was applied to ordinary Mach-Zehnder interferometer filter constituting a new type filter. The output transfer function was derived by the signal flow graph method, and the output spectra were simulated and analyzed. The results show that the improved filter can give rectangular waves appThe single microring resonator was applied to ordinary Mach-Zehnder interferometer filter constituting a new type filter. The output transfer function was derived by the signal flow graph method, and the output spectra were simulated and analyzed. The results show that the improved filter can give rectangular waves approximating flat top and flat bottom, The free spectral range up to 111 GHz, the extinction ratio of 10.2dB. Compared with Mach-Zehnder interferometer filter, free spectral range, the extinction ratio, precision are improved obviously. By changing the way of combination of micro ring resonator and Mach-Zehnder interferometer filter, more output waveforms were got. The effects of various parameters on the output performance of the device was discussed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 713003 (2015)
LD Side-pumped Passive Mode-locked Nd: YAG Laser with Semiconductor Saturable Absorption Mirror
WANG Xi, WANG Yong-gang, DUAN Li-na, LI Lu, and WANG Yi-shan
In order to obtain picoseconds pulse output, a Nd∶YAG laser passively mode-locked was proposed by a reflective semiconductor saturable-absorber mirror. Based on Z-type resonator, the laser output was obtained with repetition frequency of 101 MHz, pulses of 23.4 ps, central wavelength of 1 064 nm and average power of 35In order to obtain picoseconds pulse output, a Nd∶YAG laser passively mode-locked was proposed by a reflective semiconductor saturable-absorber mirror. Based on Z-type resonator, the laser output was obtained with repetition frequency of 101 MHz, pulses of 23.4 ps, central wavelength of 1 064 nm and average power of 356 mW, corresponding to 3.49 nJ pulse energy. The measured beam quality is about 1.2. In order to enhance the average single pulse energy of mode-locked pulse, Q-switched mode-locking operation was obtained by inserting an acousto-optic Q-switch, producing 364 mW pulses with 1.03 MHz repetition rate. The resulting 406 nJ pulse energy is 116 times larger than that from continuous mode-locking operation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 714001 (2015)
Near Infrared Quantum Cutting in Pr3+, Yb3+ Co-doped CaWO4 Phosphors
LI Yun-qing, CUI Cai-e, HUANG Ping, WANG Lei, TIAN Yue, and JIA Hai-zhen
Near-infrared quantum cutting CaWO4∶Pr3+, Yb3+ phosphors were prepared by the solid state reaction method. The effect of different concentrations of Yb3+ ions on the phase and luminescent properties of the samples was investigated by X-ray diffractometer, fluorescence spectrophotometer and luminescence lifetime decay cNear-infrared quantum cutting CaWO4∶Pr3+, Yb3+ phosphors were prepared by the solid state reaction method. The effect of different concentrations of Yb3+ ions on the phase and luminescent properties of the samples was investigated by X-ray diffractometer, fluorescence spectrophotometer and luminescence lifetime decay curve. X-ray diffraction shows that all of samples are pure scheelite-typed CaWO4. Three near-infrared emission peaks located at 1001, 1030 and 1048 nm can be found in the emission spectra upon the excitation of 453-nm light, which correspond to 2F5/2→2F7/2 transition of Yb3+ and 1D2→3F4 transition of Pr3+, respectively. The luminescence lifetime decay curve of Pr3+(652 nm) with different Yb3+ concentrations is gradually shortened with the increase of Yb3+ ions concentration, which suggests energy transfer efficiency and quantum efficiency can be improved with the increase of Yb3+ ions concentration. The highest quantum efficiency can be calculated to be 166.9%. The material may be applied in the silicon solar cells to improve its photoelectric conversion efficiency..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 716001 (2015)
Light Distribution Optimization Design of LED Street Light Based on Freeform Surface Lens
YANG Kai, LI Xiao-yan, LIN Bin, CHEN Liang, SHI Yan, and JIN Shang-zhong
In order to improve the light efficiency and illumination uniformity and reduce glare, LED street light need secondary light distribution design. Based on the basis of space Snell law, combing with bidirectional iteration algorithm and equivalent grid dividing, this paper realizes one-to-one correspondence between LED In order to improve the light efficiency and illumination uniformity and reduce glare, LED street light need secondary light distribution design. Based on the basis of space Snell law, combing with bidirectional iteration algorithm and equivalent grid dividing, this paper realizes one-to-one correspondence between LED emergent ray space and specific spot on the road. A freeform surface lens was generated, and it can convert light distribution of the LED to rectangle. Simulation results show that LED′s light energy is almost limited in a rectangular area of 30 m×13 m, the whole light efficiency is 90.4%. The horizontal illumination uniformity and vertical illumination uniformity can reach 83.2% and 71.7% respectively. When multiple LEDs are arranged in 30 m spacing, the facula width on the pavement is about 14m. At this time, vertical illumination uniformity increased to 77.2%. Experiment results show that the light distribution curve of LED street light is bat-wing distribution. The horizontal and vertical average illumination is 31.17 lx and 25.72 lx, and energy is limited in ±62° and ±40°, respectively. It can meet requirements of national standard for lighting design of urban road, which prove the feasibility and practicability of the lens design algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 722001 (2015)
Edge-lighting Natural Light Flat Panel Light without Light Guide Plate
MA Bing-xu, WEN Shang-sheng, CHEN Ying-cong, and LIU Lei
An edge-lighting natural light flat panel light without light guide plate was designed. The collector collects the nature-light, then the light is transported to the panel lights with the help of PMMA optical fiber. In order to obtain uniform illumination, the beam from the fiber was converged by using a cylindrical leAn edge-lighting natural light flat panel light without light guide plate was designed. The collector collects the nature-light, then the light is transported to the panel lights with the help of PMMA optical fiber. In order to obtain uniform illumination, the beam from the fiber was converged by using a cylindrical lens and grazed through the reflective back panel with freeform surface. Furthermore, the effect of the flat panel light was simulated by using the Tracepro software. And different illumination maps for different angles which between optical fiber and the reflective back panel were get after further simulation. The simulation shows that the uniformity of illumination can reach 94.1% after optimizing the parameters of the flat panel light. This light not only can solve the danger of LED blue light, but also simpler the production process, which has a good reference for converting sunlight into the green lighting and functional lighting..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 722002 (2015)
Oxygen Mass Flow Detection Method in Supersonic Flow Based on TDLAS
JIA Liang-quan, LIU Wen-qing, KAN Rui-feng, IU Jian-guo, YAO Lu, WEI Min, and RUAN Jun
In order to measure the Oxygen mass flow rate effectively, the absorption of Oxygen molecules around 13 144.5 cm－1 was studied based on the principle of laser Doppler frequency shift, combined with wavelength modulation spectroscopy and tunable diode laser absorption spectroscopy technology. An experimental system was In order to measure the Oxygen mass flow rate effectively, the absorption of Oxygen molecules around 13 144.5 cm－1 was studied based on the principle of laser Doppler frequency shift, combined with wavelength modulation spectroscopy and tunable diode laser absorption spectroscopy technology. An experimental system was built for supersonic air mass flow measurement based on the wavelength modulation and tunable diode laser absorption spectroscopy technology. The airflow velocity and Oxygen concentration were retrieved according to the frequency shift and the peak value of the second harmonic signal of O2 molecular. The experimental results indicate that, in the laboratory environment, the airflow velocity of the system is 707.6 m/s, the Oxygen concentration is 0.49 g/L and the mass flow rate is about 0.42 kg/s, with a measurement error of 5.46%.The experimental results can be used in Oxygen mass-flow of engine inlet measurement system miniaturize development and flight experiment by TDLAS..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 730001 (2015)
Research on in situ Detection of Chemical Contaminants Based on Multi-angle Infrared Differential Absorption Spectra
LIU Jia-xiang, FANG Yong-hua, CUI Fang-xiao, and WU Jun
In order to detect contaminants on surface, a method for surface contamination detection was developed based on multi-angle infrared differential absorption spectra. As contaminants′ absorption ability varied with measurement angles, the spectral features of contaminants could be extracted from multi-angle observationsIn order to detect contaminants on surface, a method for surface contamination detection was developed based on multi-angle infrared differential absorption spectra. As contaminants′ absorption ability varied with measurement angles, the spectral features of contaminants could be extracted from multi-angle observations. Firstly, multi-angle measurement model of chemical contaminants was introduced. Then three typical compounds: poly (dimethylsiloxane), triethyl phosphate and methyl salicylate were measured both in laboratory and field on different substrates. The results showed that, with multi-angle infrared differential absorption spectra, this method could extract directly spectral features of contaminants both in laboratory and field on typical surfaces, and spectral features of contaminants got more distinct with more smooth substrate and larger difference between two incidence angles employed. This method had application potential in immediate responding for chemical contaminants detection..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 7, 730002 (2015)
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