2010
2010
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Record 13 of
Title:Design and optimization of highly nonlinear low-dispersion crystal fiber with high birefringence for four-wave mixing
Author(s):Zhang, Ya-Ni(1,2); Ren, Li-Yong(1); Gong, Yong-Kang(1); Li, Xiao-Hui(1); Wang, Lei-Ran(1); Sun, Chuan-Dong(1)Source: Applied Optics Volume: 49 Issue: 16 DOI: 10.1364/AO.49.003208 Published: June 1, 2010Abstract:We have proposed a novel type of photonic crystal fiber (PCF) with low dispersion and high nonlinearity for four-wave mixing. This type of fiber is composed of a solid silica core and a cladding with a squeezed hexagonal lattice elliptical airhole along the fiber length. Its dispersion and nonlinearity coefficient are investigated simultaneously by using the full vectorial finite element method. Numerical results show that the proposed highly nonlinear low-dispersion fiber has a total dispersion as low as ±2:5 ps nm -1 km-1 over an ultrabroad wavelength range from 1.43 to 1:8 μm, and the corresponding nonlinearity coefficient and birefringence are about 150 W-1 km-1 and 2:5 × 10-3 at 1:55 μm, respectively. The proposed PCF with low ultraflattened dispersion, high nonlinearity, and high birefringence can have important application in four-wave mixing. ? 2010 Optical Society of America.Accession Number: 20103513193253 -
Record 14 of
Title:Low-timing-jitter, stretched-pulse passively mode-locked fiber laser with tunable repetition rate and high operation stability
Author(s):Liu, Yuanshan(1); Zhang, Jian-Guo(1,2); Chen, Guofu(1); Zhao, Wei(1); Bai, Jing(1)Source: Journal of Optics Volume: 12 Issue: 9 DOI: 10.1088/2040-8978/12/9/095204 Published: September 2010Abstract:We design a low-timing-jitter, repetition-rate-tunable, stretched-pulse passively mode-locked fiber laser by using a nonlinear amplifying loop mirror (NALM), a semiconductor saturable absorber mirror (SESAM), and a tunable optical delay line in the laser configuration. Low-timing-jitter optical pulses are stably produced when a SESAM and a 0.16 m dispersion compensation fiber are employed in the laser cavity. By inserting a tunable optical delay line between NALM and SESAM, the variable repetition-rate operation of a self-starting, passively mode-locked fiber laser is successfully demonstrated over a range from 49.65 to 50.47 MHz. The experimental results show that the newly designed fiber laser can maintain the mode locking at the pumping power of 160 mW to stably generate periodic optical pulses with width less than 170 fs and timing jitter lower than 75 fs in the 1.55 μm wavelength region, when the fundamental repetition rate of the laser is continuously tuned between 49.65 and 50.47 MHz. Moreover, this fiber laser has a feature of turn-key operation with high repeatability of its fundamental repetition rate in practice. ? 2010 IOP Publishing Ltd Printed in the UK & the USA.Accession Number: 20104713405551 -
Record 15 of
Title:Fabrication and characteristics of near elliptical core squeezed hexangular lattice photonic crystal fibers based on polymer
Author(s):Zhang, Yani(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7655 Issue: PART 1 DOI: 10.1117/12.866764 Published: 2010Abstract:The polarization properties of a new structure of high birefringence polarization maintaining photonic crystal fibers with elliptical-core triangle lattice of squeezed hexangular structure were explored. The modal birefringence and the first order polarization mode dispersion were analyzed by adopting a full-vector localized basis function method. The numerical results show that the polarization properties are strongly dependent on structural parameters of the PCF. Furthermore, the proposed fiber was fabricated based on MMA monomer polymerization method in situ. The optical properties were measured and modal birefringence was well consistent with numerical calculation. ? 2010 Copyright SPIE - The International Society for Optical Engineering.Accession Number: 20105013487346 -
Record 16 of
Title:Ultra-dry oxygen atmosphere to protect tellurite glass fiber from surface crystallization
Author(s):Zhang, Aidong(1); Lin, Aoxiang(1,2); Toulouse, Jean(1)Source: Journal of Non-Crystalline Solids Volume: 356 Issue: 9-10 DOI: 10.1016/j.jnoncrysol.2010.01.001 Published: March 15, 2010Abstract:In this study we report on surface crystallization phenomena and propose a solution for the fabrication of long and robust tellurite glass fibers. The bulk tellurite glasses of interest were prepared by melting and quenching techniques. Tellurite glass preforms and fibers were fabricated by suction casting and rod-in-tube drawing methods, respectively. The surfaces of the tellurite bulk glass samples and of the drawn fibers prepared under different controlled atmospheres were examined by X-ray diffraction. When the tellurite glass fibers were drawn in ambient air containing water vapor, four primary kinds of small crystals were found to appear on the fiber surface, α-TeO2, γ-TeO2, Zn2Te3O8 and Na2Zn3(CO3)4·3H2O. A mechanism for this surface crystallization is proposed and a solution described, using an ultra-dry oxygen gas atmosphere to effectively prevent surface crystallization during fiber drawing. ? 2010 Elsevier B.V. All rights reserved.Accession Number: 20100712706611 -
Record 17 of
Title:Design of Topas photonic bandgap fiber with high birefringence and low confinement loss
Author(s):Wang, Doudou(1,2); Wang, Lili(1)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 621 Issue: 1-3 DOI: 10.1016/j.nima.2010.05.045 Published: 2010Abstract:A highly birefringent hollow-core photonic bandgap fiber based on Topas cyclic olefin copolymer is designed. The rhombic hollow-core with rounded corners is formed by omitting four central air holes of the cladding structure. The guided modes, birefringence and confinement loss of the fiber are investigated by using the full-vector finite element method. A high phase birefringence of the order of 10-3, a group birefringence of the order of 10-2 and confinement loss less than 0.1 dB/km are obtained at the central wavelength (1.55 μm) range of the bandgap for fiber with seven rings of air holes in the cladding region. ? 2010 Elsevier B.V. All rights reserved.Accession Number: 20104213301710 -
Record 18 of
Title:Properties of photo-thermal-refractive glass
Author(s):Ren, Qing(1); Lu, Min(1); Zou, Kuai-Sheng(1); Li, Wei-Nan(1); Zhang, Xiao-Liang(2); Yu, Feng-Xia(2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 39 Issue: 5 DOI: Published: October 2010Abstract:Photo-thermal-refractive(PTR) glass is fabricated by high temperature melt process. PTR glass, a kind of sodium- zinc-aluminum-silicate glass doped with silver, cerium and fluorine, possesses both photosensitive and heat-sensitive characters. In the study, PTR glass was firstly exposed by ultraviolet light, and then after the heat treatment of the sample, the measurement of ultraviolet-visible-near infrared transmissivity spectrum and the X-ray diffraction of exposure part was performed. According to the results, the working window of PTR glass is between 400 nm and 2800 nm. The best exposure wavelength of PTR glass is 305 nm. The micro-crystallization of PTR glass can be controlled by exposure dose and conditions of two stepped heat treatment. During the treatment processes mentioned above, NaF crystal was precipitated. Because crystal particles are very tiny, visible light is not scattered in the glass.Accession Number: 20105113512505 -
Record 19 of
Title:Multistage etching process for microscopically smooth tellurite glass surfaces in optical fibers
Author(s):Zhang, Aidong(1); Lin, Aoxiang(1,2); Wang, Jau-Sheng(1); Toulouse, Jean(1)Source: Journal of Vacuum Science and Technology B Volume: 28 Issue: 4 DOI: 10.1116/1.3437017 Published: July-August 2010Abstract:Bulk samples of tellurite glass with composition 75 TeO2 -20ZnO-5 Na2O (TZN) were fabricated by melting and quenching techniques. In order to improve the surface quality of optical fiber preform made with this tellurite glass, the authors developed a multistage etching process. The relationship between successive etching treatments and roughness of the TZN glass surface was probed by using an atomic force microscope. The results demonstrate that this multistage etching method effectively improves this tellurite glass surface smoothness to a level comparable with that of a reference silica glass slide, and the corresponding chemical micromechanisms and fundamentals are discussed and confirmed by atomic force microscopy, potentially contributing to the development of multicomponent soft glass fibers and devices. ? 2010 American Vacuum Society.Accession Number: 20104013269193 -
Record 20 of
Title:Efficiency of pump absorption in gain-guided and index-antiguided (GG-IAG) fiber
Author(s):Yan, Kun-Lun(1,2); Zhou, En-Yu(3); Wei, Wei(1,3); Peng, Bo(1,3)Source: Journal of Modern Optics Volume: 57 Issue: 6 DOI: 10.1080/09500341003695610 Published: March 2010Abstract:In this paper, the absorption characteristics of a novel double-clad gain-guided and index-antiguided (GG-IAG) fiber are investigated with 3D ray-trace method. Additionally, the simulated correctness compared with real data was carried out by measuring the GG-IAG fiber. Analysis and experimental results show that the absorption characteristics of GG-IAG fibers are different from conventional fibersthe total absorption efficiency of a GG-IAG fiber is large, while the effective absorption length is very short, and the negative refractive index step has significant influence on the total absorption efficiency. ? 2010 Taylor & Francis.Accession Number: 20101912922259 -
Record 21 of
Title:Spectrum acquisition of detonation based on CMOS
Author(s):Li, Yan(1,2); Bai, Yonglin(3); Wang, Bo(3); Liu, Baiyu(3); Xue, Yingdong(1,2); Zhang, Wei(1,2); Gou, Yongsheng(1,2); Bai, Xiaohong(3); Qin, Junjun(3); Xian, Ouyang(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7658 Issue: DOI: 10.1117/12.865534 Published: 2010Abstract:The detection of high-speed dynamic spectrum is the main method to acquire transient information. In order to obtain the large amount spectral data in real-time during the process of detonation, a CMOS-based system with high-speed spectrum data acquisition is designed. The hardware platform of the system is based on FPGA, and the unique characteristic of CMOS image sensors in the rolling shutter model is used simultaneously. Using FPGA as the master control chip of the system, not only provides the time sequence for CIS, but also controls the storage and transmission of the spectral data. In the experiment of spectral data acquisition, the acquired information is transmitted to the host computer through the CameraLink bus. The dynamic spectral curve is obtained after the subsequent processing. The experimental results demonstrate that this system is feasible in the acquisition and storage of high-speed dynamic spectrum information during the process of detonation. ? 2010 Copyright SPIE - The International Society for Optical Engineering.Accession Number: 20105213525831 -
Record 22 of
Title:A video quality assessment metric based on human visual system
Author(s):Lu, Wen(1); Li, Xuelong(2); Gao, Xinbo(1); Tang, Wenjian(1); Li, Jing(1); Tao, Dacheng(3)Source: Cognitive Computation Volume: 2 Issue: 2 DOI: 10.1007/s12559-010-9040-9 Published: June 2010Abstract:It is important for practical application to design an effective and efficient metric for video quality. The most reliable way is by subjective evaluation. Thus, to design an objective metric by simulating human visual system (HVS) is quite reasonable and available. In this paper, the video quality assessment metric based on visual perception is proposed. Three-dimensional wavelet is utilized to decompose video and then extract features to mimic the multichannel structure of HVS. Spatio-temporal contrast sensitivity function (S-T CSF) is employed to weight coefficient obtained by three-dimensional wavelet to simulate nonlinearity feature of the human eyes. Perceptual threshold is exploited to obtain visual sensitive coefficients after S-T CSF filtered. Visual sensitive coefficients are normalized representation and then visual sensitive errors are calculated between reference and distorted video. Finally, temporal perceptual mechanism is applied to count values of video quality for reducing computational cost. Experimental results prove the proposed method outperforms the most existing methods and is comparable to LHS and PVQM. ? Springer Science+Business Media, LLC 2010.Accession Number: 20102212974928 -
Record 23 of
Title:An intelligent control system for X-ray framing camera
Author(s):Li, Yan(1,2); Bai, Yonglin(3); Wang, Bo(3); Liu, Baiyu(3); Xue, Yingdong(1,2); Bai, Xiaohong(3); Qin, Junjun(3); Zhang, Wei(1,2); Gou, Yongsheng(1,2)Source: 2010 International Conference on Intelligent Computation Technology and Automation, ICICTA 2010 Volume: 1 Issue: DOI: 10.1109/ICICTA.2010.244 Published: 2010Abstract:An intelligent system of X-ray framing camera is designed and realized to fulfill the demand of being intelligent and automotive in the diagnosis system for Inertial Confinement Fusion (ICF). Being controlled by PC104 embedded host computer and combining with Interface Card, the camera system can achieve human-computer interface interactive, networking, camera working point setting, mode switching and working condition monitoring. The system has characterization of self-diagnosing, self-adjusting, and self-protection, which can not only satisfy the requirements of the automotive networking test, but also realize the consistent and accurate of the measurement results, and the stability and dependability of the framing camera are improved. The experimental results show that the gate pulse jitter is confined to 10 ps, screen voltage keeps a very small variation less than 2%, rising and falling edge are shorter than 200 ns, the flat-topped time lasts for 10 us. The new system makes great significance on improving the physical diagnosis on ICF studies. ? 2010 IEEE.Accession Number: 20103413182846 -
Record 24 of
Title:Theoretical analysis of the heat dissipation mechanism in high power photonic crystal fiber lasers
Author(s):Li, Jianfeng(1); Duan, Kailiang(2); Dai, Zhiyong(1); Ou, Zhonghua(1); Liu, Yong(1); Liu, Yongzhi(1)Source: Separation and Purification Technology Volume: 74 Issue: 1 DOI: 10.1016/j.ijleo.2009.01.015 Published: July 30, 2010Abstract:Starting from the special structure of photonic crystal fiber (PCF), the heat dissipation model of a PCF laser is constructed. Based on the heat dissipation model, the temperature distributions along the radial and axial directions of the PCF (DC-Yb-17040) for forward pump of 200W and two-end pump of 100W each side are calculated numerically by using the finite element method (FEM). The results show that the temperature distribution for two-end pump mode is more even than that for forward pump mode and the maximum temperature in the fiber decreases by 178.16 °. With the thermal power in fiber core being assumed to be fixed, the effects of the core radius, outer cladding radius, and air-clad width on the temperature distribution along the fiber are analyzed numerically. The results show that the changing of core radius only affects the temperature in core region slightly and the decreasing of air-clad width decreases the temperature in inner cladding and core regions effectively. Meanwhile, the temperature of the whole fiber can be decreased by increasing the cladding radius. ? 2009 Elsevier GmbH. All rights reserved.Accession Number: 20103213122687