Journals >Acta Photonica Sinica
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2011
Volume: 40 Issue 4
28 Article(s)
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Research Article
Development of Ultra-wide Bandwidth All-optical Sampling Oscilloscope Equipment
ZHANG Jian-guo, and LIU Yuan-shan
All-optical sampling oscilloscopes are key measurement equipment for research and development of ultrahigh-speed optical communication systems and photonic switching networks. This paper briefly reports our experimental work on the design and implementation of a prototype system for ultra-wide bandwidth all-optical samAll-optical sampling oscilloscopes are key measurement equipment for research and development of ultrahigh-speed optical communication systems and photonic switching networks. This paper briefly reports our experimental work on the design and implementation of a prototype system for ultra-wide bandwidth all-optical sampling oscilloscopes, and it also presents the preliminary results obtained from our experiment on the development of such an oscilloscope prototype system. Using our developed passively mode-locked fiber laser of high stability as an optical sampling pulse source, we successfully demonstrate the all-optical sampling of optical pulse sequences with pulse width of 1.8 ps at the repetition rates of 10 GHz and 40 GHz, respectively, by means of the four-wave mixing (FWM) in a highly nonlinear fiber. Then the waveforms of ultrashort optical pulse signals are reproduced by using digital signal processing and computer image processing, respectively, in our prototype system which displays the measured optical pulses with a width of 2.3 ps. With our developed optical sampling oscilloscope prototype, we also successfully perform the accurate measurement of optical eye diagrams for 10Gbit/s and 40 Gbit/s optical data signals (of 1.8 ps pulse width) which are modulated with a pseudorandom bit sequence, respectively. This is the first report in China about the practical development work on ultra-wide bandwidth all-optical sampling oscilloscope equipment and the associated experimental test results. The obtained results on all-optical waveform measurement of ultrashort optical pulse signals are also compared with those measured by the conventional optoelectronic measurement system consisting of a 70 GHz wideband electronic oscilloscope and an ultrafast photodetector. It is shown clearly that our developed all-optical sampling oscilloscope prototype has much higher temporal resolution and larger system bandwidth than a conventional optoelectronic measurement system does..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 487 (2011)
Improved Discrete Layer-peeling Method for the Reconfiguration of Multi-channel Fiber Bragg Grating
BAI Qing, and FENG De-jun
The discrete layer-peeling method for designing multi-channel fiber Bragg grating was optimized. Through the new method, after inserting different phase changes at different channels, the coupling coefficients was then fitted by Gaussian function to get a lower and more smooth refractive index modulation. The simulatioThe discrete layer-peeling method for designing multi-channel fiber Bragg grating was optimized. Through the new method, after inserting different phase changes at different channels, the coupling coefficients was then fitted by Gaussian function to get a lower and more smooth refractive index modulation. The simulation results show that a 8-channel fiber Bragg grating is successfully designed using the proposed method with the maximum refractive index modulation of 0.000 5, much lower than that of traditional DLP method (0.001 3), which decreases the requirement of fiber′s optical sensitivity. And, the difficulty of inscribing a fiber grating was reduced by smoothing the refractive index modulation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 505 (2011)
Thermal Effect Analysis for the Yb3+doped Fiber Amplifier
YANG Chun-bo, LENG Jin-yong, and LU Qi-sheng
In order to study Stimulated Brillouin Scattering(SBS) in Yb3+-doped double clad single-frequency fiber amplifier,thermal effects of the fiber amplifier were analyzed theoretically,based on the rate equations and heat transfer equations.The impacts of the fiber temperature,which can broaden the SBS gain profile and supIn order to study Stimulated Brillouin Scattering(SBS) in Yb3+-doped double clad single-frequency fiber amplifier,thermal effects of the fiber amplifier were analyzed theoretically,based on the rate equations and heat transfer equations.The impacts of the fiber temperature,which can broaden the SBS gain profile and suppress SBS,on the amplifier performances were discussed.The relationships between the SBS and pump power,signal power,heat transfer coefficient were simulated.The results of simulation provide theoretical guide to optimum design of high power single-frequency fiber amplifier..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 509 (2011)
The Effects of the Attachment of Oxygen on the UV Filament in Air
HUI Zhi-zhou, XU Yin, JI Xian-ming, and ZHANG Hua
From the Maxwell wave equation, the beam propagation equation, which includes several nonlinear effects, such as the attachment of oxygen, was obtained. The filamentation dynamics was homologous to the problem of particles moving in a potential well. The initial conditions in which the laser beam becomes a stationary fFrom the Maxwell wave equation, the beam propagation equation, which includes several nonlinear effects, such as the attachment of oxygen, was obtained. The filamentation dynamics was homologous to the problem of particles moving in a potential well. The initial conditions in which the laser beam becomes a stationary filamentation were analyzed. By the numerical simulation, the influences of beam size, power and phase on the attachment of oxygen in the filament propagation were discussed. The conclusions indicate that the power is rather consumed by the attachment of oxygen, which results in the beam size decreasing in oscillation process. The results qualitatively explain the relationship between beam size and power..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 514 (2011)
Theoretical Calculation of Linewidth Enhancement Factor in GaAs Semiconductor Lasers
ZHANG Fan, LI Lin, WANG Yong, ZOU Yong-gang, LI Zhan-guo, MA Xiao-hui, SUI Qing-xue, and LIU Guo-jun
The effects of interband transition, free carrier absorption and bandgap narrowing on linewidth enhancement factor (α factor) in semiconductor lasers were comprehensively considered in a simple model. A convenient calculation method of α factor in semiconductor lasers was presented. The formula for α factor was derivedThe effects of interband transition, free carrier absorption and bandgap narrowing on linewidth enhancement factor (α factor) in semiconductor lasers were comprehensively considered in a simple model. A convenient calculation method of α factor in semiconductor lasers was presented. The formula for α factor was derived at first, the gain of GaAs semiconductor lasers was theoretically analyzed and calculated, and the process of solving the Fermi integral function by taking advantage of the Mupad notebook in MATLAB software was introduced. Further, the effect of interband transition on α factor was calculated based on the peak variation of gain fitting curves. Finally, both the effects of free carrier absorption and bandgap narrowing on α factor were disscused, respectively, and their values were obtained.The results show that interband transition and bandgap narrowing have more obvious effects on α factor in semiconductor lasers (α factor are 22.562 and -6.853, respectively) than the effect of free carrier absorption(α factor is only -0.605)..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 521 (2011)
Detecting Equation of Spacebore Laser Rangefinder to Particle-target
DI Hui-Ge, HUANG Geng-hua, SHU Rong, and WANG Jian-Yu
Maximum range is one of the major parameters of laser rangefinder and a basic guideline in system design.It will change with the detected goal.The detecting equation of lidar to particle-target was educed in this paper,and it could be used easily in practice.Laser′s far-field distributing affect maximum range.AccordingMaximum range is one of the major parameters of laser rangefinder and a basic guideline in system design.It will change with the detected goal.The detecting equation of lidar to particle-target was educed in this paper,and it could be used easily in practice.Laser′s far-field distributing affect maximum range.According to the practical detecting equation,the maximum range of a laser rangfinder was estimated,and it changed among 15.05~20.6 km with laser′s far-field distributing.The result was analyzed and discussed.It was found that if laser′s far-field distributing is flat and other parameters of the laser rangefinder is not changed,the system′s maximum range can be improved to 18.9 km..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 526 (2011)
Bistable Anisotropy in One-dimensional Coupled Cavity Optical Waveguides with Kerr Defect
LI Wen-hui, BI Wei-hong, and WANG Jin-sheng
An one-dimensional (1D) coupled cavity optical waveguides (CCOWs) with Kerr defect was proposed. It was a Kerr medium doped into a high refractive index medium layer in CCOWs. The optical bistability (OB) of the structure was investigated by using one-dimensional transfer matrix method and nonlinear transfer matrix metAn one-dimensional (1D) coupled cavity optical waveguides (CCOWs) with Kerr defect was proposed. It was a Kerr medium doped into a high refractive index medium layer in CCOWs. The optical bistability (OB) of the structure was investigated by using one-dimensional transfer matrix method and nonlinear transfer matrix method. The linear properties of this structure, including the characterics of the field distribution and the shift of low-frequency band edge modes, were analyzed by one-dimensional transfer matrix method. The principle of the OB realized by the structure was discussed. It is found that different incident directions have different bistability threshold, because the refractive index of the defect layer is changed by three order nonlinear effect of Kerr medium stimulated by the localization of optical field in the defect layer. The field distribution in defect layer was related to the incident light direction. The properties of the OB were studied by the nonlinear transfer matrix method. The results indicate that the threshold of the forward direction (from left to right) is a half lower than that of the backward one (from right to left), because the localization behaviour of the forward direction is larger than that of the backward direction due to the position of the defect layer..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 529 (2011)
Design and Fabrication of Inverted Ridge Waveguide Electro-Optic Modulator Based on PDMS Material
LI Xiao-dong, TAN Zhen-yu, WANG Fei, ZHENG Hong-li, SUN Xiao-qiang, and ZHANG Da-ming
Polydimethylsiloxane is a kind of silicone which has merits of cost effective, good dielectric properties, and lower optical transmission loss in infrared range. Since the Poly［(methyl methacrylate)-co-(Disperse Red 1 methacrylate)］ is applied as the active layer, in order to avoid the passive influence between the corPolydimethylsiloxane is a kind of silicone which has merits of cost effective, good dielectric properties, and lower optical transmission loss in infrared range. Since the Poly［(methyl methacrylate)-co-(Disperse Red 1 methacrylate)］ is applied as the active layer, in order to avoid the passive influence between the core and claddings, polydimethylsiloxane was chosen to be the cladding layer. An inverted ridge polymer waveguide Mach-Zehnder Electro-Optic modulator was designed and fabricated. Aiming at the deposition phenomena which arises when only using SF6 in polydimethylsiloxane reactive ion etching, a method of utilizing the mixture of SF6 and O2 was proposed for polydimethylsiloxane reactive ion etching process. It was found that when the flux ratio of SF6∶O2 is 50 sccm∶10 sccm, the groove has the best shape. Through the optical test, the fabricated inverted ridge Mach-Zehnder waveguide has a good near-infrared light output. Co-planar waveguide electrodes based on Aluminum material were designed and fabricated, and signal response of electro-optic modulator was observed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 533 (2011)
A Narrow-band Subwavelength Plasmonic Waveguide Filter with Metal-insulator-metal Bragg Reflector
ZHONG Xiao-lan
The finite-difference time-domain method was used to simulate the extraordinary optical transmission in a one-dimensional metal-insulator-metal Bragg reflector. It was shown that when introducing a finite array of periodic grooves on the two surface of metal-insulator-metal waveguide, the photonic band gap and pass banThe finite-difference time-domain method was used to simulate the extraordinary optical transmission in a one-dimensional metal-insulator-metal Bragg reflector. It was shown that when introducing a finite array of periodic grooves on the two surface of metal-insulator-metal waveguide, the photonic band gap and pass band will appear. The position of grooves corresponded to the abdominal position of electric field amplitude distribution at resonance wavelength of the metal-insulator-metal waveguide. It was found that the central wavelength of the pass band is around with the resonance wavelength of the metal-insulator-metal waveguide. By adjusting the geometric structure of the grooves and using asymmetrical multi- metal-insulator-metal Bragg reflectors, a good narrowband filtering effect can be found. The central wavelength of pass band is near the resonance wavelength and the full-width at half-maximum is far less than the central wavelength.The required wavelength can be choosen and the other wavelengths can also be restrained by the proposed method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 537 (2011)
Effects of Linewidth Enhancement Factor on the Nonlinear Period-one Oscillation of a Semiconductor Laser with External Optical Injection
ZhANG Ming-jiang, LIU Tie-gen, LI Jing-xia, and WANG Yun-cai
The linewidth enhanment factor is one of the key parameters for semiconductor lasers. The value of linewidth enhanment factor is different in kinds of type semiconductor lasers. The dependency of the nonlinear period-one oscillation in optically injected semiconductor on the linewidth enhanment factor was numerically iThe linewidth enhanment factor is one of the key parameters for semiconductor lasers. The value of linewidth enhanment factor is different in kinds of type semiconductor lasers. The dependency of the nonlinear period-one oscillation in optically injected semiconductor on the linewidth enhanment factor was numerically investigated, with the single-mode rate-equation of optical injection semiconductor laser. The results show that linewidth enhancement factor strongly affect the dynamical behavior of the system. As the linewidth enhancement factor increases, the range of the period-one oscillation and its frequency increase, and the injection locking stable state is suppressed greatly. Moreover, the optical spectrum and frequency of the period-one oscillation were investigated. The results reveal that the frequency of the period-one oscillation increases as the linewidth enhancement factor, injection strength and frequency detuning increasing..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 542 (2011)
Third-order Nonlinear Optical Properties Study of ［(C3H7)4N］［Au(C3S5)2］ Applied to All-optical Switches
LI Guo-chao, REN Quan, WANG Xin-qiang, YANG Hong-liang, CHEN Jing-wei, and CAI Ning-ning
A novel novel dmit2- salt: ［(C3H7)4N］［Au(C3S5)2］ was synthesized. Its acetonitrile solution with concentration 1.0 ×10-3 mol/L was prepared. The thin film with ［(C3H7)4N］［Au(C3S5)2］-doped in PMMA was fabricated spin-coating on a quartz substrate. The third-order optical nonlinearities of sample solution and film wA novel novel dmit2- salt: ［(C3H7)4N］［Au(C3S5)2］ was synthesized. Its acetonitrile solution with concentration 1.0 ×10-3 mol/L was prepared. The thin film with ［(C3H7)4N］［Au(C3S5)2］-doped in PMMA was fabricated spin-coating on a quartz substrate. The third-order optical nonlinearities of sample solution and film were investigated by using the laser Z-scan technique with 20 ps pulses width at 1 064 nm. The experimental results show that the third-order nonlinear susceptibility χ(3) improves an approximate 3 orders of magnitude by the PrAu film over the solution. The nonlinear refraction coefficient n2 and the third-order nonlinear susceptibility χ(3) of the PrAu film were obtained to be 1.76×10-15 m2/W and 9.37×10-10 esu, respectively. The results suggest that PrAu will be a promising material for all-optical switching devices..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 547 (2011)
Incoherently Coupled Grey Photovoltaic Soliton Families due to Two-photon Photorefractive Effect
JIANG Qi-chang, SU Yan-li, and JI Xuan-mang
To study the grey photovoltaic soliton families in two-photon photovoltaic photorefractive materials under open-circuit conditions, the dynamical evolution equation and the numerical solution of the grey photovoltaic soliton families were established. The existence curves of the grey photovoltaic soliton families were To study the grey photovoltaic soliton families in two-photon photovoltaic photorefractive materials under open-circuit conditions, the dynamical evolution equation and the numerical solution of the grey photovoltaic soliton families were established. The existence curves of the grey photovoltaic soliton families were simulated by the numerical method. The results show that the soliton families are derived under the assumption that the multiple carrier beams share the same polarization, wavelength, and are mutually incoherent. Such grey photovoltaic soliton families reduce to grey-grey photovoltaic soliton pairs when they contain only two components. Furthermore, such grey soliton families will reduce to dark soliton families or soliton pairs when the greyness of soltion takes zero. Relevant examples were presented where the photovoltaic photorefractive material was LiNbO3..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 552 (2011)
Relationship of Surface Plasmon Polaritons and Nanoparticles Morphology
ZHAO Wei, and ZHAO Xiao-peng
The relationship of surface plasmon polaritons and morphology of nanoparticles was researched by tailoring the particle′s surface morphology. Roughened silver nanoparticle was prepared by aqueous chemical method and further fabricated into composite structured metamaterial, the optical behavior of as-prepared sample waThe relationship of surface plasmon polaritons and morphology of nanoparticles was researched by tailoring the particle′s surface morphology. Roughened silver nanoparticle was prepared by aqueous chemical method and further fabricated into composite structured metamaterial, the optical behavior of as-prepared sample was measured then. The experimental results are contrasted with the one of dendrites and smooth-surface particles. The results show that metamaterials effect does not appear in smooth-surface particles, however, the peculiar effect appears in flower-like particles and dendritic particles with lower and higher intensity, respectively. By altering the structure of a particle′s surface, the properties of surface plasmons can be significantly changed, and the manipulation on light propagation can also be realized..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 556 (2011)
Preparation of Electro-Optic Waveguide Based on KH560 Modified Organic/Inorganic Hybrid Materials
WANG Xi-bin, CAO Zi-jian, JIN Lin, REN Dian-fu, and ZHANG Da-ming
A kind of silane coupling agent KH560-based organic / inorganic hybrid electro-optic (E-O) material was synthesized by Sol-Gel method. The reaction mechanism of hydrolysis and condensation of KH560 in the case of hydrochloric acid as a catalyst was analysed. Then the surface morphology, refractive index and E-O propertA kind of silane coupling agent KH560-based organic / inorganic hybrid electro-optic (E-O) material was synthesized by Sol-Gel method. The reaction mechanism of hydrolysis and condensation of KH560 in the case of hydrochloric acid as a catalyst was analysed. Then the surface morphology, refractive index and E-O properties of the thin films were characterized by means of atomic force microscopy (AFM), ellipsometry, and simple reflection method. At last, the poled polymer films with good shape and alterable refractive index were obtained. The E-O coefficient was measured to be 3.5 pm/V @1 310 nm wavelengh based on the simple reflection method. According to the flexibility of this material, the structure of the strip-loaded waveguide was designed.And the two-dimensional and three-dimensional light fields were also simulated by the Opti-BPM software. After exploring the processing technology, the fabrication of the waveguide with strip-loaded structure was completed. Finally the near-field images of this waveguide were obtained..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 561 (2011)
Magnetization in the Uniaxial Crystal Induced by Highly Focusing Laser Beam
SHI Tian-zhen, and ZHANG Yao-ju
Based on the vector diffraction theory, magnetization distributions induced by tightly focusing circularly polarized laser pulses were analyzed in the uniaxial crystal with the inverse Faraday effect. The dependence of the magnetization distributions on the position of the interface was studied. The magnetization distrBased on the vector diffraction theory, magnetization distributions induced by tightly focusing circularly polarized laser pulses were analyzed in the uniaxial crystal with the inverse Faraday effect. The dependence of the magnetization distributions on the position of the interface was studied. The magnetization distributions in the uniaxial crystal with small birefringence effect and in the isotropic medium were compared. Numerical results show that when the interface is closed to the lens, the positions of the maximum magnetization intensity and the minimum magnetization spot shift along the optical axial direction. The magnetization intensity in the uniaxial crystal is bigger than that in the isotropic medium, but the size of the magnetization spot in the uniaxial crystal is smaller than that in the isotropic medium. For larger ratio (defined as a ratio of the anisotropic optic-magneto constant to the isotropic optic-magneto constant in the uniaxial crystal), magnetization intensity is larger but the magnetization spot is smaller..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 565 (2011)
Strip-loaded Waveguide Electro-optic Modulator Based on Bonded Organic-inorganic Hybrid Material
ZHANG Feng, LI Xiao-dong, TAN Zhen-yu, LI Tao, CHEN Chang-ming, and ZHANG Da-ming
Compared with common organic-inorganic materials, side chain bonded organic-inorganic material has better thermo-stability, and can avoid crystallization and phase separation. And the relaxation of ordered polarized chromophore is restricted as the movement of chromophore is blocked. A kind of stable, good-performance Compared with common organic-inorganic materials, side chain bonded organic-inorganic material has better thermo-stability, and can avoid crystallization and phase separation. And the relaxation of ordered polarized chromophore is restricted as the movement of chromophore is blocked. A kind of stable, good-performance side chain bonded organic-inorganic material was compounded and applied as the electro-optic layer.Conventional semiconductor processing was applied to fabricate strip-loaded waveguide structure and the Mach-Zehnder(M-Z) electro-optic modulators were made.Response signal of 10 kHz was observed at 1 550 nm light source..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 569 (2011)
Design and Analysis of the Scattering Light Collection System for Substrates in Laser-gyro
YANG Kai-yong, WEI Zhi-meng, LONG Xing-wu, and LIU Jian-ping
Application of light scattering measurement in the inspection of fused silica substrates for laser-gyro application was studied. It was found that collecting objective is more propitious to eliminate volume scattering than integrating sphere and more appropriate to the measurement of scattering light for directly detecApplication of light scattering measurement in the inspection of fused silica substrates for laser-gyro application was studied. It was found that collecting objective is more propitious to eliminate volume scattering than integrating sphere and more appropriate to the measurement of scattering light for directly detecting supersmooth surfaces of fused silica substrates. Collecting objective(N.A. is 0.4) was designed by ZEMAX and volume scattering from points whose axile distances are more than 1.5 millimeters was eliminated completely. To solve the drift problem of photomultiplier tube, specific structure of collecting system was designed, so that scattering light and reflecting light can strike on the same photmulitplier tube on separate time. It was found that the drift problem of photomultipolier tube can be solved with this setting, so that the stability of the scattering measurement system over long time span can be improved greatly and its practicability in engineering is ensured..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 573 (2011)
A Differential Algorithm Based on PCF-LPG to Eliminate Noise of the Fiber Sensor
WANG Yun-peng, ZHAO Chun-liu, DONG Xin-yong, and KANG Juan
A differential algorithm based on a long-period grating in a photonic crystal fiber was proposed to eliminate the noise of fiber sensors and raise the accuracy of fiber sensors. Utilizing the property temperature insensitive and wide transmission spectrum of the long-period grating, the intensities of two signals locatA differential algorithm based on a long-period grating in a photonic crystal fiber was proposed to eliminate the noise of fiber sensors and raise the accuracy of fiber sensors. Utilizing the property temperature insensitive and wide transmission spectrum of the long-period grating, the intensities of two signals located respectively within the positive and negative linear region of the long-period grating′s transmission spectrum could be monitored simultaneously and accurately. The noise of fiber sensors was eliminated effectively by the algorithm of two signals, since the two signals (also including the noise of fiber sensors) transmit through the same way to the monitor. When the differential algorithm based on the long-period grating in photonic crystal fiber was applied in a high-birefringence fiber loop mirror temperature sensor, experimental results show that the differential algorithm eliminates the broadband source fluctuations and all of power fluctuations in the system, and raises the accuracy of the sensor by the differential algorithm based on the long-period grating in a photonic crystal fiber. The value of the algorithm remains constant when the power of light source varies ±10% and the relative error between the measured temperature change and the true change is only 0.04 and 0.03. Compared with the sensing without the algorithm, the accuracy increases from ~76% to ~97%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 578 (2011)
Rectangular-hole Photonic Crystal Fibers
HE Zhong-jiao
By employing a full-vector finite-element method and anisotropic perfectly matched layers, a novel rectangular-hole photonic crystal fiber is fully investigated and a method to achieve high birefringence of the photonic crystal fiber is proposed. Simulation results show that birefringence property of the rectangular-hoBy employing a full-vector finite-element method and anisotropic perfectly matched layers, a novel rectangular-hole photonic crystal fiber is fully investigated and a method to achieve high birefringence of the photonic crystal fiber is proposed. Simulation results show that birefringence property of the rectangular-hole photonic crystal fibers is almost the same as the elliptical-hole photonic crystal fiber which can achieve the high birefringence up to the order of 0.01. Both the rectangular-hole photonic crystal fiber and the elliptical-hole photonic crystal fiber have the similar properties such as the mode profile, birefringence, confinement loss and so on..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 583 (2011)
Stripe-reduction of the Push-broom Interferential Imaging Spectrometer
CAO Wei-liang, LIAO Ning-fang, CUI De-qi, and TAN Bo-neng
The structure and work principle of push-broom interferential imaging spectrometer was analyzed. It was found that the brightness of interferential data was non-uniform along the slit direction by the processed error of slit, the stripe noises along the push-broom direction were added on the restored spectral-image cubThe structure and work principle of push-broom interferential imaging spectrometer was analyzed. It was found that the brightness of interferential data was non-uniform along the slit direction by the processed error of slit, the stripe noises along the push-broom direction were added on the restored spectral-image cube, image quality was degraded, and spectral information was difficult to evaluated. The corrected coefficient method was used to reduce stripes, and several coefficient-extracted methods were discussed. The non-uniformity of interferential data was extracted from the calibration of instruments, and the corrected coefficient was multipled by the interferential data to reduce the stripes. The results show that numerous stripes are reduced. Without the on-orbit calibration data, the coefficient is modified by the spectral-image cube contained uniform targets, and the remanent stripes are reduced efficiently by the modified coefficient..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 587 (2011)
Design of a Small Rapid Scanning Near Infrared Spectroscopy
SHI Man-man, and HUANG Mei-zhen
The design method, simulation and test results of a small rapid scanning type near-infrared spectrometer (NIR) based on improved Czerny-Turner optical structure were presented. To reduce the stray light caused by multiple diffractions and multiple reflections, the optical structure was arranged and optimized by the CarThe design method, simulation and test results of a small rapid scanning type near-infrared spectrometer (NIR) based on improved Czerny-Turner optical structure were presented. To reduce the stray light caused by multiple diffractions and multiple reflections, the optical structure was arranged and optimized by the Cary principle. The simulation and analysis result using optical software TracePro were also presented. Stray light was suppressed in the improved structure effectively. On the order hand, in order to increase the scanning speed, a harmonic motor was used to drive the grating directly instead of the traditional structure with a screw driver between the motor and the grating. Finally some basic test results of the near infrared spectrometer were presented, and glucose solution was analyzed by qualitative experiments..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 591 (2011)
Quantization Simulation and Fidelity Validation of Infrared Staring Imaging Sensors
ZHANG Fu-di, ZHANG Jian-qi, and XU Yin
Aiming at the new generation of infrared staring imaging sensors, primary physical effects modeling of imaging system elements was accomplished based on thermal infrared radiative transfer and energy conversion in imaging physical processes. The simulation model, which is different from those qualitative models availabAiming at the new generation of infrared staring imaging sensors, primary physical effects modeling of imaging system elements was accomplished based on thermal infrared radiative transfer and energy conversion in imaging physical processes. The simulation model, which is different from those qualitative models available now, quantitatively represents the modulation characteristics of input information by design parameters of imaging system elements. Through building the signal response model, spatial transfer model, spatial sampling model, and noise characterization model for infrared imaging sensors, a perfect simulator could be established and high-fidelity simulation could be realized for the imaging process. For credibility validation of the simulation model, an experiment platform was constructed to capture the system performance curve and output image of a real infrared camera. Subsequently the similarities of performance curves and output images between the simulator and the real device were calculated and compared, and a quantitive evaluation of the simulation fidelity was made. Finally, the credibility of the simulation model was validated by the fidelity data..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 596 (2011)
Analysis of Ground Targets′S Surface Temperature Irradiated Through Artificial Illuminator
DU Shi-ming, LV Xiang-yin, FENG Yun-song, ZHANG Wei, ZENG Kai, CHEN Shan-jing, and WU Guang-ye
Based on the physical model of which the targets were irradiated through artificial illuminator in normal circumstance, the calculation model of surface temperature was built through building heat conduction differential equations and altering the outedge radiation power. Combing the calculation of surface temperature Based on the physical model of which the targets were irradiated through artificial illuminator in normal circumstance, the calculation model of surface temperature was built through building heat conduction differential equations and altering the outedge radiation power. Combing the calculation of surface temperature related to targets′s geographical circumstance and orientation, taking the Hefei building′s eastward surface for example, the surface temperature was simulational calculated and discussed in different irradiation times and illumination parameters. The results show that altering the targets′s outedge namely the targets are irradiated through artificial illuminatorm, the temperature of targets are changed, the degree of variety is determined by illuminator′s power, distance, incident angle, and in general conditions, the surface temperature is changed obviously in the night, but not in the daytime..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 602 (2011)
Entanglement Properties of Two-atoms Interacting with Field in Dissipative Cavity
ZHANG Li-hui, and LI Gao-xiang
By means of the quantum theory, the interaction between two-atoms located inside a dissipative cavity and single-mode coherent field was studied. The entanglement properties, between two atoms and between two-atoms and light fields, were analyzed. In addition, the reason that the decay of the cavity field and the detunBy means of the quantum theory, the interaction between two-atoms located inside a dissipative cavity and single-mode coherent field was studied. The entanglement properties, between two atoms and between two-atoms and light fields, were analyzed. In addition, the reason that the decay of the cavity field and the detuning between the atom and cavity field affect the evolution of entanglement was discussed. The results show that when there is cavity loss, entanglement between the atoms and light fields may occur, however entanglement gradually disappear in the long time limit. Also, the detuning between the atom and cavity field significantly affects the entanglement.The entanglement between two atoms initially in the maximally entangled states is gradually weakened due to the decay of the light field, but the detuning between the atom and the cavity field can inhibit this decay..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 607 (2011)
Quantum Properties of the Field in the System of Coupled V-type Three-level Atoms Interacting with Coherent Field in Kerr Medium
LI Ke, and LING Wei-jun
The quantum properties of the light field in the system of two coupled V-type atoms interacting with coherent field in Kerr medium were studied. The solution describing the dynamics process of the system was gained by means of the coupled Tavis-Cummings model in quantum optics. Influences of the initial state, the detuThe quantum properties of the light field in the system of two coupled V-type atoms interacting with coherent field in Kerr medium were studied. The solution describing the dynamics process of the system was gained by means of the coupled Tavis-Cummings model in quantum optics. Influences of the initial state, the detuning of the field, the coupling strength of dipole-dipole interaction between atoms and Kerr coefficient on the second-order correlation function and the squeezing parameter of the field were discussed. Numerical calculation results show: when the average photon number of the field in the initial state is smaller, the field exhibits apparent quantum effect; when the probability amplitude of the excited states of the atoms in the initial state changing from small to large, the anti-bunching effect of the field becomes more obvious, but the squeezing depth increase at first and then decrease; the detuning changing create small influence on the quantum properties of the field, its changing only change the oscillating period of the second-correlation function and the squeezing parameter of the field; the increasing of the coupling strength between the atoms weaken the anti-bunching effect of the field and make the squeezing depth become shallow; the increasing of Kerr coefficient enhances the anti-bunching effect of the field, but makes the squeezing depth become shallow..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 613 (2011)
Efficient Entanglement Distribution by Separable States
CAI Hong, and CHEN Jiong
An effcient entanglement distribution protocol was proposed using a qudit (4-dimensional space) as a separable mediating ancilla. Two qubits were used to describe a qudit in order to simplify the description. Firstly, both of the two ancilla qubits and the two distant qubits (a and b) were formed into a four-qubit unloAn effcient entanglement distribution protocol was proposed using a qudit (4-dimensional space) as a separable mediating ancilla. Two qubits were used to describe a qudit in order to simplify the description. Firstly, both of the two ancilla qubits and the two distant qubits (a and b) were formed into a four-qubit unlockable bound entangled state, called the Smolin state. Then, a projective measurement in the Bell basis was performed on the two ancilla qubits and the measurement results was delivered to a and b. Based on the measurement results, the qubits a and b can be converted into a standard singlet state locally. At any stage of the protocol, the two ancilla qubits was always separable from the subsystem (a and b). This scheme provides an effective way to distribute the maximally entangled states by separable states, and presents a concise formalism to describe and understand this physical process..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 622 (2011)
Effect of Spatial Coherence and in Incident X-ray Photon Energies on Clinical X-ray In-line Phase-contrast Imaging
XIA Tian, ZHANG Xue-long, MA Jun-shan, CHENG Jing-hai, and HUANG Yong
X-ray source is usually considered as a monochromatic point source, regardless of whose size effect. However, in clinical practical applications, an X-ray tube is a polychromatic source with a finite focal spot. The incident X-ray source was supposed as the average intensity distribution of a qusi-monochromatic light cX-ray source is usually considered as a monochromatic point source, regardless of whose size effect. However, in clinical practical applications, an X-ray tube is a polychromatic source with a finite focal spot. The incident X-ray source was supposed as the average intensity distribution of a qusi-monochromatic light circular source in the beginning, and then it was extended to the polychromatic case. Based on Fresnel-Kirchhoff diffraction theory, taking the spatial coherence into account, the new in-line X-ray Phase-contrast imaging formula was derived by Fourier transform. The absorption contrast transmission function γre and phase contrast transmission function γre2πλR2u2/M were obtained from the new formula, which represented absorption effect and phase effect, respectively. The curves of the above functions for different radiuses were given by software Matlab and the optimal positions for different source radiuses were also calculated. The theoretical analysis results are as follows: 1) the spatial coherence effect should be considered when source radius is bigger enough, and decreasing the source radius would increase phase effect; 2) there is the definitive relationship between the radius and the optimal imaging position, which has been presented in a special case；3) the effect of source size on phase effect is not infinite, which could be ignored when the size is equal to a suitable value. The suitable radius is given in a special case; 4) decreasing incident X-ray photon energies would strengthen PE obviously, and the variation of photon energies has no effect on the optimal imaging position; as a result, the new formula could be extended to the polychromatic case. In order to verify the theoretical results, the micro-focus X-ray phase-contrast imaging experiments for the breakage surface of optical glass detection were carried out. Some experimental results are in good agreement with theoretical analysis, while some do not meet our expectations. The related explanations were also presented..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 627 (2011)
An Adaptive Feature and Weight Selection Method Based on Gabor Image for Face Recognition
LIU Zhong-hua, YIN Jun, and JIN Zhong
To overcome the negative effect of factors such as illumination and expression on face recognition, an adaptive feature and weight selection method was proposed. The method was based on Gabor image for face recognition. Firstly, 40 independent feature matrices which were reconstructed with the same scale and the same dTo overcome the negative effect of factors such as illumination and expression on face recognition, an adaptive feature and weight selection method was proposed. The method was based on Gabor image for face recognition. Firstly, 40 independent feature matrices which were reconstructed with the same scale and the same direction transform results of the different face images were obtained by regarding every Gabor wavelet transformed output image as an independent sample. In order to enhance the robustness to facial expression and illumination variations, the contribution of each new feature matrix could be adaptively computed by the proposed adaptive weight method. Secondly, after applying discrete cosine transform to each feature matrix, the coefficients which had more power to discriminate different classes than others were selected by discrimination power analysis to construct feature vectors. And, linear discriminant analysis features were extracted to fulfill recognition task. Experiments on the face databases demonstrate the effectiveness of the proposed method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 4, 636 (2011)
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