Journals >Acta Photonica Sinica
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2005
Volume: 34 Issue 12
41 Article(s)
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Research Article
Investigation of the Influence of the Crystal Geometry Configuration on Self-pumped Phase Conjugate Properties
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Based on self-pumped phase conjugation experiment in Cu-doped KNSBN crystal, the influence of the photorefractive crystal geometry configuration on self-pumped phase conjugate properties was investigated.The maximum output configuration is funded in variety in the position.The different configuration carry with them coBased on self-pumped phase conjugation experiment in Cu-doped KNSBN crystal, the influence of the photorefractive crystal geometry configuration on self-pumped phase conjugate properties was investigated.The maximum output configuration is funded in variety in the position.The different configuration carry with them corresponding maximum output position.The action of crystal geometry configuration on the two coupled interaction regions self-pumped phase conjugate mechanism was analyzed with theory.The relation between geometry configuration and incident position and beam path and beam-coupling coefficient was built.The optimal work position in self-pumped phase conjugation effect was given..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1761 (2005)
Study on Beam Aperture and Space Array in ICF Target Area
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Beam aperture and space array in ICF target area are researched. Based upon the geometrical space required by the machining design of the reflector module in target chamber as well as the special requirements of large aperture and alignment devices,the relationship between beam aperture and space alignment in ICF targeBeam aperture and space array in ICF target area are researched. Based upon the geometrical space required by the machining design of the reflector module in target chamber as well as the special requirements of large aperture and alignment devices,the relationship between beam aperture and space alignment in ICF target area,which is suitable for the general technical requirement of SG-ш,facility is discussed.The equation that Δ_ vertical and Δ_ horizontal should satisfy is derived..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1766 (2005)
The Thermal Lens Focus Of The End-pumped Nd∶YAG Laser
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A new method to measure the thermal lens of the solid state laser is presented while laser is outputted by the comparation with the theory result and the experiment. The thermal lens can be achieved by experiment at first, then calculated out by the theory analysis. The thermal lens resonance cavity model is set up at A new method to measure the thermal lens of the solid state laser is presented while laser is outputted by the comparation with the theory result and the experiment. The thermal lens can be achieved by experiment at first, then calculated out by the theory analysis. The thermal lens resonance cavity model is set up at first,then the waist of the laser is calculated and the DPL′s far field divergence angle can be measured by the edge of knife method .In the end , using the laser′s spread and lens′ transfer theory , the focus of the thermal lens is known. This is a new method to measure the focus of the thermal lens of the end-pumped Nd∶YAG Laser. The result shows that the theory value is in good agreement with the experiment value. It shows that this method is correct and can be operated easily. Because the experiment is done when the DPL outputs laser , the focus of the thermal lens is gotten according to the circumstance of the laser and the precision is high..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1769 (2005)
Research of Fiber-waveguide Automatic Alignment Aystem
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Three auto-aligning methods are designed,which are called the half value method, the barycenter one and the one based on genetic algorithm (GA),respectively.The auto-aligning system model is completed. Taking single mode fiber as standard waveguide,the experiment and the results show the average end-coupling losses areThree auto-aligning methods are designed,which are called the half value method, the barycenter one and the one based on genetic algorithm (GA),respectively.The auto-aligning system model is completed. Taking single mode fiber as standard waveguide,the experiment and the results show the average end-coupling losses are less than 0.1 dB,and the standard deviations are less than 0.012 dB at the wavelength 1310 nm and 1550 nm,respectively.This process only needs 2 minutes.When it comes to the experiment of fiber-SiO_2 waveguide,the results suggest the average end-coupling losses are not more than 0.15 dB,and the standard deviations are less than 0.025 dB at the wavelength 1310 nm and 1550 nm,respectively.The whole process is accomplished within 8 minutes.It shows that the methods and system have good performances..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1773 (2005)
Research of the Fabrication Method for Color-equivalent-gray Masks
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The database method,a new mask design method is presented,which is based on the color-equivalent-gray theory.Choosing different values of red,green and blue to form different colors,masks composed of these colors can be obtained by color film recorder.The output mask is used to linearly modulate the exposure.ConsequentThe database method,a new mask design method is presented,which is based on the color-equivalent-gray theory.Choosing different values of red,green and blue to form different colors,masks composed of these colors can be obtained by color film recorder.The output mask is used to linearly modulate the exposure.Consequently,the linearization of steps can be realized.The theoretical calculation and the experimental result of sixteen-step Fresnel are given.As a result,the database method is feasible.It provides a new approach for the gray expansion and has some referential meaning for the fabrication of DOEs..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1778 (2005)
The Fabrication of Low Cost Si-based Continuously Tunable 1.55μm RCE Photodetector
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A novel method for fabricating low cost Si-based continuously tunable long wavelength resonant cavity enhanced (RCE) photodetectors was reported,in which InGaAs epitaxy layers were bonded to silicon substrates without any special treatment on bonding surfaces,employing the silicate gel as bonding medium.A thermally tunA novel method for fabricating low cost Si-based continuously tunable long wavelength resonant cavity enhanced (RCE) photodetectors was reported,in which InGaAs epitaxy layers were bonded to silicon substrates without any special treatment on bonding surfaces,employing the silicate gel as bonding medium.A thermally tunable Si-based InGaAs RCE photodetector operating at 1.3~1.6 μm was obtained,with a quantum efficiency of about 44% at the resonant wavelength of about 1.5 μm and a FWHM of about 12.5 nm.A tuning range of 14.5 nm and a 3 dB bandwidth of 1.8 GHz were obtained. This device was fabricated with traditional processes,thus the cost was decreased. It demonstrates a great potential for industry processes..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1783 (2005)
Theory and Experiment of Increasing the Extinction Ratio of the Cascaded Long Period Gratings Utilizing the Fiber Loop Mirror
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The interferometric spectrum of the cascaded long period gratings (LPG) has been modulated, and it is presented that the extinction ratio can be doubled when a fiber loop mirror is connected at the end of the cascaded LPGs, which has been proved by the experiment. The fiber loop mirror is indeed an effective and simpleThe interferometric spectrum of the cascaded long period gratings (LPG) has been modulated, and it is presented that the extinction ratio can be doubled when a fiber loop mirror is connected at the end of the cascaded LPGs, which has been proved by the experiment. The fiber loop mirror is indeed an effective and simple way to increase the extinction ratio..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1788 (2005)
Spectral Response Performance of Transmission-mode GaAs Photocathode in Activation
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The spectral response performance of transmission-mode GaAs photocathode after high-temperature activation and low-temperature activation was measured by the use of on-line spectral response measurement technology, and the integral sensitivity and spectral response performance parameters of the GaAs photocathode after The spectral response performance of transmission-mode GaAs photocathode after high-temperature activation and low-temperature activation was measured by the use of on-line spectral response measurement technology, and the integral sensitivity and spectral response performance parameters of the GaAs photocathode after high-temperature activation and low-temperature activation were compared. It was found that compared to high-temperature activation, the integral sensitivity after low-temperature activation increased 13%, and both the cut-off wavelength and peak wavelength had a slight move towards long-wave. The comparison of obtained on-line measurement curves and the spectral response curve of sealed third generation imaging intensifier was further made, and it was found that there was great difference between the spectral response curves before and after sealing..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1792 (2005)
Influence of Ridge Width on Its Frequency Bandwidth of Traveling-wave Electroabsorption Modulators
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According to the microwave properties of the traveling-wave electroabsorption modulator (TW-EAM) transmission line, an equivalent circuit model was presented and a GaAs/GaAlAs TW-EAM for 850 nm has been fabricated. The influence of the ridge width on the frequency bandwidth was driven by analyzing the characteristic imAccording to the microwave properties of the traveling-wave electroabsorption modulator (TW-EAM) transmission line, an equivalent circuit model was presented and a GaAs/GaAlAs TW-EAM for 850 nm has been fabricated. The influence of the ridge width on the frequency bandwidth was driven by analyzing the characteristic impedance Z_0, microwave transmission constant γ and S_ 21. A reduced velocity mismatch between optical wave and microwave and an impedance mismatch were demonstrated for the narrower ridge width. Potential frequency bandwidth of 23.9 GHz of a TW-EAM was predicted by theoretical simulation when the ridge width was 2 μm..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1795 (2005)
The Investigation of Controllable Phase Liquid Crystal Spatial Light Modulator
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In the paper,the phase modulation of parallel aligned LC wass discussed theoretically. The theoretical results were simulated with computer.Liquid crystal spatial light modulator(LCSLM) with parallel alignment TFT was prepared.And its properties of phase modulation were investigated.The results indicated that phase wasIn the paper,the phase modulation of parallel aligned LC wass discussed theoretically. The theoretical results were simulated with computer.Liquid crystal spatial light modulator(LCSLM) with parallel alignment TFT was prepared.And its properties of phase modulation were investigated.The results indicated that phase was controllable in the range of applied grey levels.The depth of modulation was up to 0.7 μm.And the precision was 0.052 μm.The experiment was conducted on the ZYGO interferometer,and good results were obtained..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1799 (2005)
Study on Measurement Method of Thermal Performances for High Power LED and its Applications
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The maesurement principle and procedure based on the dynamic electrical measurement method for thermal resistance and junction temperature of high power LED and the factors which influenced measuring results were investigated.At the same time,the setup of the test system for the measuring of thermal resistance was desiThe maesurement principle and procedure based on the dynamic electrical measurement method for thermal resistance and junction temperature of high power LED and the factors which influenced measuring results were investigated.At the same time,the setup of the test system for the measuring of thermal resistance was designed.The experimental results show that the metod has the advantages of simple structure and good stability,and it can be performed to measure thermal resistance and junction temperature of high power LED as a effective measurement method..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1803 (2005)
Study of the Effect of the Sensing Head Dispersion Property Upon the Sensitivity of a Bulk-glass Optical Current Transformer
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The dispersion property of the optical glass sensing head and its effect upon the sensitivity of a bulk-glass optical current transformer were theoretically analyzed by taking the Jones′ Matrix as a mathematical tool, simulated with a computer and verified with an experiment. In an optical current sensing system,when tThe dispersion property of the optical glass sensing head and its effect upon the sensitivity of a bulk-glass optical current transformer were theoretically analyzed by taking the Jones′ Matrix as a mathematical tool, simulated with a computer and verified with an experiment. In an optical current sensing system,when the fluctuations of the driving current or the ambient temperature of the optical source occurs, the peak wavelength of the source would change.It would result in the fluctuation of the sensitivity of the system because of the existing of the dispersions of the reflection-induced retardance,Verdet constant and the linear birefringence inside the sensing head.The investigation results showd that the dispersions would obviously affect the scale factor of the system.Therefore,it was necessary to stabilize the driving current and the ambient temperature of the optical source by some technical means.These results might be useful for the researchers and designers who works in the optical current sensin.
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1807 (2005)
The Temperature Compensation Design of An Optical Fiber Liquid Level Sensor with Fabry-Perot Cavity
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The impact of temperature to a fiber Fabry-Perot cavity depth is analyzed. A novel design of optical fiber liquid level sensor for compensating the temperature is introduced. The developed structure ensures that the cavity length keeps constant when the temperature changes. The sensor can be applied in the inflammable The impact of temperature to a fiber Fabry-Perot cavity depth is analyzed. A novel design of optical fiber liquid level sensor for compensating the temperature is introduced. The developed structure ensures that the cavity length keeps constant when the temperature changes. The sensor can be applied in the inflammable and explosive circumstance, for accurate automatic measurement..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1810 (2005)
Optical Fiber Sensor for the Measurement of Marine Natural Gas Hydrates Phase Change
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An optical fiber sensor used in the simulating experiment of marine natural gas hydrates to measure the phase change of marine natural gas hydrates was introduced.The intensity change of transmission light during hydrates states change was measured by the sensor to determine the phase change.Dual optical path constructAn optical fiber sensor used in the simulating experiment of marine natural gas hydrates to measure the phase change of marine natural gas hydrates was introduced.The intensity change of transmission light during hydrates states change was measured by the sensor to determine the phase change.Dual optical path construction was employed in the optical fiber sensor in order that a high measuring precision would be obtained.The light intensity of reference beam was measured to compensate the fluctuation of light source while the intensity of transmission light was measured simultaneously.Besides,dual detectors were used in each photoelectric transfer circuit to eliminate the influence of dark current of the photodetector..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1814 (2005)
Design of A Hybrid Diffractive/Refractive Achromatized Telecentric F-θ Lens System
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A hybrid diffractive/refractive achromatized telecentric f-θ lens system had been designed with a hybrid diffractive/refractive lens and three refractive lenses. The entrance pupil was placed at the focal plane so that it was a telecentric system. Contrast to the US patent 4,925,279, the lateral color reduced by one-orA hybrid diffractive/refractive achromatized telecentric f-θ lens system had been designed with a hybrid diffractive/refractive lens and three refractive lenses. The entrance pupil was placed at the focal plane so that it was a telecentric system. Contrast to the US patent 4,925,279, the lateral color reduced by one-orderinmagnitude(from2.40mmto0.23mm), andthemaximaltransverseaberrationreducedfrom260μm、1350 μm、2090 μm to 5 μm、250 μm、318 μm for 0°、14° and 20° field of views, and the maximal field curvature reduced from 8 mm、10 mm、13 mm to 0.5 mm、1 mm、6 mm for the aforementioned field of views. The designed f-θ lens system could be applied in color scanning systems, such as color laser printers and color digital photo printers. It could also be applied in high energy scanning systems. When applying the designed hybrid diffractive/refractive achromatized telecentric f-θ lens system to the high energy scanning system, a big laser machine operating in one longitudinal mode could be replaced by a small multi-mode operating laser machine,and the system could be simplified greatly and the accuracy could be proved..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1818 (2005)
Optical System Design of Star Sensor with wide-view field and Small F-number
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This paper presented an optical system of star sensor. The lens system was a complicated double- Gauss configuration which had an effective focal length of 51 mm, an F-number of F/1.1, a field of view of 21°×21°(2ω=30°),and a working wavelength rang of 0.5~0.85 μm. The difference from common lens usThis paper presented an optical system of star sensor. The lens system was a complicated double- Gauss configuration which had an effective focal length of 51 mm, an F-number of F/1.1, a field of view of 21°×21°(2ω=30°),and a working wavelength rang of 0.5~0.85 μm. The difference from common lens used in imaging system was that this lens system was required to have a high resolving power in the geometric pattern of stars. It was required to deliver the geometric spot dispersion in the specific rang at its focal surface and lower difference of displacements of centroids from thief ray in the interesting spectral range..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1822 (2005)
Design of a Short Focal-length Zoom System
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A method for initial zoom system design was proposed.The new optimized arithmetic was used for designing based on differential analytic expression method.The results showed that the length of the system could be reduced in this way.An example of three moving group elements and mechanic compensator type was given with cA method for initial zoom system design was proposed.The new optimized arithmetic was used for designing based on differential analytic expression method.The results showed that the length of the system could be reduced in this way.An example of three moving group elements and mechanic compensator type was given with configuration f′=3.87~19.35 mm,ω=76.6°~17.71°..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1825 (2005)
Experimental Investigation
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Applying self-focusing lens as a key device for optical sensor in fiber digital holographic system, one fiber carried the beam for illuminating the object and the others conveyed the reference beam to the CCD. The reflective wave scattered from the object surface was collected with a self-focusing lens to interfere witApplying self-focusing lens as a key device for optical sensor in fiber digital holographic system, one fiber carried the beam for illuminating the object and the others conveyed the reference beam to the CCD. The reflective wave scattered from the object surface was collected with a self-focusing lens to interfere with the reference beam on the CCD target.The lensless Fourier transform holograms thus formed were digitally recorded and the experimental results show that the reconstructed images and the interferogram can be evaluated for object deformation. It is shown that with the use of a self-focusing lens by its special imaginary property, the fiber system presented here can be used for measuring small areas of an object or objects difficult to access, while the whole setup is compact and more flexible..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1829 (2005)
Diagnosing Microwave Plasma Thruster′s Plume by Digital Holographic Interferometry
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The distribution properties of Microwave Plasma Thruster′s plume are studied with the digital holographic interferometry.By numerically reconstructing the digital hologram,the phase distribution of MPT′s plume is obtained, from which the electron density is also calculated.By employing the phase multiplication method,tThe distribution properties of Microwave Plasma Thruster′s plume are studied with the digital holographic interferometry.By numerically reconstructing the digital hologram,the phase distribution of MPT′s plume is obtained, from which the electron density is also calculated.By employing the phase multiplication method,the fringe density of the interference pattern obtained by digital hologram was multiplied to reveal the refractive index distribution of the plume field more intuitively.It is shown that the digital holographic interferometry is an effective method for diagnosing MPT plasma′s plume..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1833 (2005)
Measurement Analysis of Atmospheric Aerosol Aerodynamics Size with APD Detector
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Measurement analysis of atmospheric aerosol with APD detector was described.Aatmospheric particles went through laser beam which was scattered.The scattering light of particles through two parallel laser beams was detected by an APD (avalanche photoelectric diode) detector,by forming a double-peaks signal,and the fly-tMeasurement analysis of atmospheric aerosol with APD detector was described.Aatmospheric particles went through laser beam which was scattered.The scattering light of particles through two parallel laser beams was detected by an APD (avalanche photoelectric diode) detector,by forming a double-peaks signal,and the fly-time of the particles was obtained.The instrument was calibrated with standard particles.It can be used to measure the size distribution of atmospheric aerosol particles.The standard spectrum was obtained by analyzing the experimental data of different size particles,and measured the atmospheric aerosol particles and standard particles.The experiment results agreed with the theory very well..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1837 (2005)
Wave Front Dislocations of Gaussian-Shell Beams in a Turbulent Atmosphere
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The appearance of wave-front circle edge dislocations and the relationship between the location of the wave-front dislocations of a Gaussian-Shell beam,which was propagating in a weak turbulent atmosphere and in near ground,and the parameters of the turbulent-strength and the distance of propagation had been discussed The appearance of wave-front circle edge dislocations and the relationship between the location of the wave-front dislocations of a Gaussian-Shell beam,which was propagating in a weak turbulent atmosphere and in near ground,and the parameters of the turbulent-strength and the distance of propagation had been discussed by the Rytov approximation and the short-term statistical averaging-position of dislocation that was developed in this paper.The relationship between the positions of the wave-front dislocations of the Gaussian-Shell beams propagation in turbulent atmosphere and the atmospheric turbulence strength, the beam propagation distance were analyzed based on a approximation model that the co-axial combined beams and the intersecting combined beams propagated in turbulent atmosphere.The formulas of the statistical average radius of wave-front circle edge dislocations had been developed for the coaxes beams that had different beam diamantes and crossbeams in the cases that the averaging time was shorter t.
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1841 (2005)
Real Time Correction of Atmospheric Refractive Error Based on NURBS Curve Interpolation
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A technology,which integrated the traditional algorithm of tracing by every vertex with NURBS curve interpolation method,was put forward.This technology was applied in high precision and real time correction of atmospheric refractive error field of many visible light measure equipments.Some shortcomings such as large qA technology,which integrated the traditional algorithm of tracing by every vertex with NURBS curve interpolation method,was put forward.This technology was applied in high precision and real time correction of atmospheric refractive error field of many visible light measure equipments.Some shortcomings such as large quantity calculation,nonreal time calculate of algorithm of tracing by every vertex could be overcome by this method.The method was particularly fit for correcting the atmospheric refractive error in the real time data interpretation of full-automatic film interpretoscopes or optic-electronic theodolite..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1845 (2005)
Effect of the atmospheric turbulence on laser communication system
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First,transmission equation of the laser transmitting through atmospheric turbulence channel was analyzed,ignoring other noises in the system,atmosphere turbulence was the only cause for Bit Error Rate(BER).Then,the amplitude variance and intensity variance of the laser signal were discussed,and the relationship betwweFirst,transmission equation of the laser transmitting through atmospheric turbulence channel was analyzed,ignoring other noises in the system,atmosphere turbulence was the only cause for Bit Error Rate(BER).Then,the amplitude variance and intensity variance of the laser signal were discussed,and the relationship betwwen BER and the laser communication system was deduced.The result indicated that in the weak variance condition intensity variance should be below 0.67 for communication system with BER below 10 -9;with turbulence intensity C2_n increasing,BER increased rapidly;adopting laser with longest wave to communicate can decrease BER effecively..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1850 (2005)
Numerical Simulation on Effect of Saturation Length for Few-Mode Fiber Grating
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The reflection characteristics of few mode fiber Bragg grating (FM-FBG) with non-uniform profile of index change were numerically studied. The reflection spectrum of FM-FBG was obtained by solving the coupled mode equation using shooting method. Under the condition that the maximum index change at the core-cladding intThe reflection characteristics of few mode fiber Bragg grating (FM-FBG) with non-uniform profile of index change were numerically studied. The reflection spectrum of FM-FBG was obtained by solving the coupled mode equation using shooting method. Under the condition that the maximum index change at the core-cladding interface and absorption coefficient were constant, the numerical results indicated that the reflectivity of cross-mode coupling peak between LP_ 01 and LP_ 11 modes varies parabolically with the saturation length of index change. When saturation length was small, the reflectivity of cross-mode coupling increased with saturation length and reached a maximum value. With the further increasing saturation length,the reflectivity of cross-mode coupling decreased gradually to zero when saturation length increased to the diameter of fiber core. It was also indicated that the peak reflectivities, which correspond to forward modes coupled to the same order back-ward modes, increased monotonically with saturation length..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1853 (2005)
Failure Location Method Based Case Database
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Alarm case which corresponding to failure could be listed by analyzing and filtering alarm information of network management,accordingly,a failure location method based on alarm case database was proposed.The method accelerated failure location and simplified the processing of failure location.In addition,the case dataAlarm case which corresponding to failure could be listed by analyzing and filtering alarm information of network management,accordingly,a failure location method based on alarm case database was proposed.The method accelerated failure location and simplified the processing of failure location.In addition,the case databse which was used for failure location was open to operators,which meant case of database could be added,deleted and modified easily,so it made failure location easy for administration and maintenance..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1858 (2005)
Simulation Analysis of Optical Characteristics of Drude Inhomogeneous Coatings
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On the basis of Drude theory,the relationship of refractive index and the deposition rate ,which were changeable in the course of deposition of inhomogeneous coatings,was discussed firstly.Then using computer aided simulation,the optical characteristics of inhomogeneous dielectric coatings,which was mixture of differenOn the basis of Drude theory,the relationship of refractive index and the deposition rate ,which were changeable in the course of deposition of inhomogeneous coatings,was discussed firstly.Then using computer aided simulation,the optical characteristics of inhomogeneous dielectric coatings,which was mixture of different materials from different evaporated sources,was also discussed.The discussion included single period and multi-periods,positive change and negative change,integral and half-baked periods,etc.The minimum of transmittance attenuated by thrice polynomial of periods was discovered,and the negative Drude inhomogeneous coatings with half-baked periods was the optimization design of Notch filters..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1862 (2005)
The Effects of Increased UV-B Radiation,NaCl Stress and Their Combined Treatment on the Photosynthesis and Flavone Metabolism in Wheat Seedlings
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During increased UV-B radiation,NaCl strees and their combined treatment,measuring the net photosynthetic rate,stomatal conductance,intercellular CO~~2 concentration,PAL activity,the contents of chlorophyll and flavone of first leave of wheat seedlings respectively.The net photosynthetic rate,stomatal conductance and iDuring increased UV-B radiation,NaCl strees and their combined treatment,measuring the net photosynthetic rate,stomatal conductance,intercellular CO_2 concentration,PAL activity,the contents of chlorophyll and flavone of first leave of wheat seedlings respectively.The net photosynthetic rate,stomatal conductance and intercellular CO_2 concentration of wheat seedlings were reduced by NaCl stress and increased UV-B radiation;In comparison with NaCl stress,NaCl + UV-B did not influence the net photosynthetic rate,stomatal conductance and intercellular CO_2 concentration of wheat seedlings; PAL activity and content of flavone of wheat seedlings were enhanced by increased UV-B radiation,NaCl stress and their combined treatment.The main reason of inhibition of photosynthesis by increased UV-B radiation was stomatal limitation;In NaCl + UV-B treatment,the reduction effect of increased UV-B radiation on photosynthesis of wheat seedlings could be weakened by NaCl stress..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1868 (2005)
Study on Image Fusion between Visible Images and Infrared Image in θ-modulated Multi-spectral Photography
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A new method is represented based on wavelet transform for image fusion and pseudo-coloring in multi-spectral photography with θ-modulation.Its features are as follows:The decoded image in visible band and infrared image′s low frequency components are fused with improved Weighted Average Method, and the fusion image′s A new method is represented based on wavelet transform for image fusion and pseudo-coloring in multi-spectral photography with θ-modulation.Its features are as follows:The decoded image in visible band and infrared image′s low frequency components are fused with improved Weighted Average Method, and the fusion image′s high frequency components are obtained using local energy difference of two images as the fusion criterion.The fused images are synthesized into a pseudo-color in RGB color space.The theoretical analysis and experiment results show that with this method,good fusion performance and pseudo-color result can be achieved..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1889 (2005)
A Method of Image Edge Detection Based on Multiple Edge Features and FCM
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An edge detection method of the infrared image based multiple features and the fuzzy C-means algorithm (FCM) is proposed. The multiple edge features are defined according to the character of the gray intensity distribution at the image edge. An vector is composed by the multiple edge features, then the vectors of all pAn edge detection method of the infrared image based multiple features and the fuzzy C-means algorithm (FCM) is proposed. The multiple edge features are defined according to the character of the gray intensity distribution at the image edge. An vector is composed by the multiple edge features, then the vectors of all pixels in input image are worked out, and compose a data set that can reflect the natural characters of image edge, then divide the data set into two clusters of the edge data set and not edge data set by FCM. Our method does not need any threshold; more sensitive for weak edge detection; has better anti-noise performance since the influence of noise is adequately considered when the feature vector is selected..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1893 (2005)
Background Estimation Algorithm Based on Multi-Resolution and Block
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In the video sequence,the difference of consecutive image is Gauss.A detection approach of background and target block was proposed which was constructed by characters of the kurtosis and deflection of Gaussian random variable.And the idea of multi-resolution was inducted to grade and block the different image. An apprIn the video sequence,the difference of consecutive image is Gauss.A detection approach of background and target block was proposed which was constructed by characters of the kurtosis and deflection of Gaussian random variable.And the idea of multi-resolution was inducted to grade and block the different image. An approach of background estimation based on grade and block is constructed.The simulation was done by computer.The experimenting result of this method was valid and fast..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1897 (2005)
A Region-based Remote Sensing Image Fusion Method
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A region-based image fusion method was proposed.The source images firstly were split into different regions with various spatial characteristics and then performed the different fusion methods for each particular region independently.Experiments were implemented with two categories of remote sensing image fusion—multisA region-based image fusion method was proposed.The source images firstly were split into different regions with various spatial characteristics and then performed the different fusion methods for each particular region independently.Experiments were implemented with two categories of remote sensing image fusion—multispectral image vs.panchromatic image and multispectral image vs.radar image.The results show that using the proposed method which could be not only obtained better quality fusion result,but also easily controlled the contribution of these components in the fused product and chosen the appropriate fusion method,which satisfied the user′s needs..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1901 (2005)
A Fast Approach to Face Location and Normalization
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A new method for human face image scale and direction estimation is proposed using covariance matrix eigenvalue and eigenvector of edge set,which is proved by theory and experiments.Based on the method,a novel approach to face location and normalization is presented,which is proved to be fast and precise.A new method for human face image scale and direction estimation is proposed using covariance matrix eigenvalue and eigenvector of edge set,which is proved by theory and experiments.Based on the method,a novel approach to face location and normalization is presented,which is proved to be fast and precise..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1906 (2005)
Analysis on the Temperature Fluctuating of FOG′s Source
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For the purpose of improving precision and practicability of Fiber Optic Gyroscope, the thermal fabrication of SLD module was analyzed and a detailed description of the all-digital control system had been carried out.The testing result indicated that in a temperature range of -15℃ to 55℃,it restrained the temperature fFor the purpose of improving precision and practicability of Fiber Optic Gyroscope, the thermal fabrication of SLD module was analyzed and a detailed description of the all-digital control system had been carried out.The testing result indicated that in a temperature range of -15℃ to 55℃,it restrained the temperature fluctuating of SLD.This technology yielded a much better stability of SLD′s wavelength 0.014% and output power 0.4%,which conduced to a much better performance of FOG..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1910 (2005)
Design and Realization of the Microcomputer System of Multispectral Digital Camera Based on Single Chip Computer and CPLD
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The design and realization of the microcomputer System of multispectral digital camera based on single chip computer and CPLD had been introduced. Single chip computer was the core of the system,and a CPLD had been used to extend the control interface of it.The CPLD was programmed by VHDL and graphic editor,and made thThe design and realization of the microcomputer System of multispectral digital camera based on single chip computer and CPLD had been introduced. Single chip computer was the core of the system,and a CPLD had been used to extend the control interface of it.The CPLD was programmed by VHDL and graphic editor,and made the CPLD a multiple-use I/O interface chip.The design not only predigested the circuit, minished the size of circuit board and reduced the power dissipation, but also was easy to modify the configure of interface.And it fit for applications of microcomputer system of the multispectral camera..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1914 (2005)
The Application of Fuzzy-PID Control in TV Follow Servo System
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A new method based on the fuzzy–PID control was presented which was suitable for TV follow servo system.The advantages of simple fuzzy control and traditional PID control were combined in this method.A designing method of fuzzy–PID controller was given,then an example of how to design and simulate the system by using tA new method based on the fuzzy–PID control was presented which was suitable for TV follow servo system.The advantages of simple fuzzy control and traditional PID control were combined in this method.A designing method of fuzzy–PID controller was given,then an example of how to design and simulate the system by using the software MATLAB was introduced.The simulation results show that the performance of TV follow servo system is improved by using the proposed controller..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1918 (2005)
The Study at Automatic Focusing Systems and Methods of Calibrated Focal Length Used in Precision Measurement
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Introduced a method of controlling and calibrating focal length about zoom lens used in precision measurement in High-Speed TV Measurement Instrument.Systems adopted PC104 SysCentreModule,Motion Controller and Step Motor to realize precision control in the zoom systems.In addition,correct lens systematic error by preciIntroduced a method of controlling and calibrating focal length about zoom lens used in precision measurement in High-Speed TV Measurement Instrument.Systems adopted PC104 SysCentreModule,Motion Controller and Step Motor to realize precision control in the zoom systems.In addition,correct lens systematic error by precise calibrated focal length.In this method,it became possible that High-Speed TV Measurement Instrument Systems based on zoom lens were used in trajectory measurement and to improve measurement accuracy in shooting range greatly..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1921 (2005)
A Digital Inclination Angle Measurement System With Temperature Compensation
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A digital inclination angle measurement system with temperature compensation is proposed,and the structure of the system,the principle of temperature compensation and the software design of the system are clarified in details.The system that includes inclinometer,single-chip,A/D converter and temperature sensor has achA digital inclination angle measurement system with temperature compensation is proposed,and the structure of the system,the principle of temperature compensation and the software design of the system are clarified in details.The system that includes inclinometer,single-chip,A/D converter and temperature sensor has achieved inclination angle measurement of high precision in a wide temperature range and has eliminated the warp brought by temperature.The precision of this system is verified by experimentation.This system has the merits of high stability,high precision and good linearity. In some measurement systems of high precision,this system will be widely used..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1925 (2005)
Physical Optics
Studies on the Defect Mode Properties of 1D Photonic Crystal
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The photonic band gap structure of 1D photonic crystal with an absorptive defect layer was studied by using the transfer matrix method, and presented formulas for the defect mode height and its full width at half maximum (FWHM) under the first-order Taylor′s approximation in the vicinity of central wavelength. InvestigThe photonic band gap structure of 1D photonic crystal with an absorptive defect layer was studied by using the transfer matrix method, and presented formulas for the defect mode height and its full width at half maximum (FWHM) under the first-order Taylor′s approximation in the vicinity of central wavelength. Investigations shown that the extinction coefficient,the number of periods and the width of the defect layer had significant effects on the properties of the defect mode.When these parameters increased,the defect mode height decreased quickly. However,the FWHM of the defect mode relied mainly on the number of periods,it decreased quickly with increasing the number of periods, but it changed slightly with the extinction coefficient and the defect layer width..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1876 (2005)
Distribution of Transmitted Light of a Glan-Taylor Prism
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Based on design feature of Glan-Taylor prism,and by using Snell′s law and equal thickness interference,the distribution of transmitted light of an air-spaced polarizing prism with the incidence of collimated light beam and convergent wave were studied as a function of azimuth and incident angle.Experiments accordingly Based on design feature of Glan-Taylor prism,and by using Snell′s law and equal thickness interference,the distribution of transmitted light of an air-spaced polarizing prism with the incidence of collimated light beam and convergent wave were studied as a function of azimuth and incident angle.Experiments accordingly were conducted,and both theoretical and experimental results indicated that equal visibility and width of fringe were got with the incidence of collimated light;unequal visibility and width of fringe were got with the incidence.
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1881 (2005)
Influence of Transmission Characteristics of Beam Deflector on Orienting Accuracy
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The distribution of base mode Gaussian beam′s electric field through LiNbO3 deflector is calculated based on the beam refraction theory in the media interface and the vectorial theory of propagation in anisotropic media.The model of the intermediate frequency current, from the detector of beam orienting system, versus The distribution of base mode Gaussian beam′s electric field through LiNbO3 deflector is calculated based on the beam refraction theory in the media interface and the vectorial theory of propagation in anisotropic media.The model of the intermediate frequency current, from the detector of beam orienting system, versus beam mismatched angle is rebuilt.The computer simulation results demonstrate the effect of output electric field change on the intermediate frequency current as a function of mismatched angle.High beam orienting precision can be obtained based on the revised mathematical model..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1885 (2005)
Quantum Optics
Emission Probability of a Non-degenerate Two-photon Mazer
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The quantum theory of the two-photon mazer,previously limited to the degenerate case,is extended to the non-degenerate situation.The analytical expression for the atomic emission probability is obtained and the corresponding behavior is investigated.The results show that the emission probability behaviors in the non-deThe quantum theory of the two-photon mazer,previously limited to the degenerate case,is extended to the non-degenerate situation.The analytical expression for the atomic emission probability is obtained and the corresponding behavior is investigated.The results show that the emission probability behaviors in the non-degenerate two-photon mazer differ from those in the degenerate two-photon mazer,since two cavity modes are allowed in the mazer so that there are two freedoms changing the potentials that the atoms experience as they transit the cavity..
Acta Photonica Sinica
- Publication Date: Dec. 25, 2005
- Vol. 34, Issue 12, 1872 (2005)
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