2010
2010
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Record 193 of
Title:Spectral property of two-photon flux generated by four-photon scattering in photonic-crystal fibers
Author(s):Sun, Hongbo(1); Liu, Xueming(1); Hu, Xiaohong(1); Li, Xiaohui(1)Source: Optical Engineering Volume: 49 Issue: 12 DOI: 10.1117/1.3516732 Published: December 2010Abstract:Based on the scalar four-photon scattering process, the quantum state of a lightwave at the output of fiber is derived by solving the nonlinear Schrdinger equation with a perturbation theory. The joint spectral function of two photons is achieved from the derived quantum state. The dispersion operator involves the third-order dispersion term in the case that the pump wavelength is close to the zero dispersion wavelength. Simulation results show the first-order approximation of our joint spectral function is in excellent agreement with the complicated exact solution. By analyzing the spectral property of the two-photon flux generated by four-photon scattering in photonic-crystal fibers, it is found that the sign of dispersion has very little influence on the spectrum except the slight modulation instability in the anomalous dispersion domain. ? 2010 Society of Photo-Optical Instrumentation Engineers.Accession Number: 20112013988468 -
Record 194 of
Title:Energy quantisation for dissipative solitons
Author(s):Wang, L.R.(1); Liu, X.M.(1); Gong, Y.K.(1); Mao, D.(1); Li, X.H.(1)Source: Electronics Letters Volume: 46 Issue: 6 DOI: 10.1049/el.2010.0359 Published: 2010Abstract:The energy quantisation effect for dissipative solitons is experimentally observed in an erbium-doped fibre laser with large normal-cavity-dispersion. Experimental results reveal that the steady dissipative solitons tend to be restricted by an upper energy limit and the increment of pump power approaches to a constant with respect to the pulse number. ? 2010 The Institution of Engineering and Technology.Accession Number: 20101212800915 -
Record 195 of
Title:Third-order nonlinear optical properties of GeS2-Sb 2S3-CdS chalcogenide glasses
Author(s):Guo, Haitao(1); Hou, Chaoqi(1); Gao, Fei(1); Lin, Aoxiang(1); Wang, Pengfei(1); Zhou, Zhiguang(1); Lu, Min(1); Wei, Wei(1); Peng, Bo(1)Source: Optics Express Volume: 18 Issue: 22 DOI: 10.1364/OE.18.023275 Published: October 25, 2010Abstract:The third-order nonlinear optical properties of GeS2-Sb 2S3-CdS chalcogenide glasses were investigated utilizing the Z-scan and femtosecond time-resolved optical Kerr effect (OKE) methods at the wavelength of 800nm, respectively. The compositional dependences were analyzed and the influencing factors including the linear refractive index, the concentration of lone electron pairs, the optical bandgap and the amount of weak covalent/ homopolar bonds were discussed. A glass, i.e. 76GeS 2·19Sb2S3·5CdS, with large nonlinear refrative index (n2 = 5.63 ′ 10-14 cm 2/W), low nonlinear absorption coefficient (β = 0.88 cm/GW) and minimum figure of merit (FOM = 2 βλ/n2 = 2.51)was finally prepared. The electronic contribution in weak heterpolar covalent and homopolar bonds are responsible for large n2 in chalcogenide glass, and the Sheik-Bahae rule combining the Moss rule are proved to be an effective guidance for estimating the third-order nonlinearities and further optimizing the compositions in chalcogenide glasses. ? 2010 Optical Society of America.Accession Number: 20104613380490 -
Record 196 of
Title:The Influence of SiO2 shell on fluorescent properties of LaF3:Nd3+/SiO2 core/shell nanoparticles
Author(s):Bo, Peng(1,3); Kai, Cui(1,2); Chao, Gao(1); Wei, Wei(3)Source: Journal of Nanomaterials Volume: 2010 Issue: DOI: 10.1155/2010/238792 Published: 2010Abstract:Distinct effects of the Si O 2 shell on fluorescence properties of LaF 3:Nd3+/SiO2 core/shell nanoparticles were demonstrated by annealling the nanoparticles at different temperatures. Emission spectra, excitation spectra, and decay curves of the nanoparticles were measured. A significant improvement of fluorescence intensity was observed for LaF3:Nd3+/SiO2core/shell nanoparticles annealed at 900 °C. The phenomenon is ascribed to the change of environment of LaF3:Nd3+ core which is imposed by SiO2 shell. And the change is confirmed by the excitation spectra. It provides a useful way to improve fluorescent intensity of the Si O 2-coated La F 3:N d 3+ nanoparticles. The lifetime for nanoparticles annealed at 900 °C shows a slight decrease contrast with nanoparticles annealed at 400 and 600 °C. This is caused by the higher phonon energy of SiO2 than that of La F 3. Copyright ? 2010 Cui Kai et al.Accession Number: 20110113546715 -
Record 197 of
Title:A new package structure for high power single emitter semiconductor lasers
Author(s):Zhang, Yanxin(1); Wang, Jingwei(1); Peng, Chenhui(1); Li, Xiaoning(1); Xiong, Lingling(1); Liu, Xingsheng(1,2)Source: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010 Volume: Issue: DOI: 10.1109/ICEPT.2010.5582809 Published: 2010Abstract:High power semiconductor lasers have found increased applications in pumping solid state or fiber laser systems for industrial, military and medical applications as well as direct material processing applications. The reliability requirement for high power semiconductor lasers has been increased in recent years and it has been proven that indium-free packaging is one of the most effective ways in improving lifetime. The performance including reliability of high power semiconductor lasers is highly depended on the package structure. We have designed a new package structure for high power single emitter semiconductor lasers which is called F-mount. In contrast to traditional single emitter package structures, the F-mount offers indium-free packaging while improving or at least not sacrificing the thermal management. The heat sink of this new structure is insulated and easy for system integration. Finite element numerical analysis was used to compare the thermal resistance between F-mount structure and traditional structure. It was found that F-mount has high power and high electrical-to-output efficiency than the traditional structure. Lifetime testing was conducted on the F-mount devices and it was found that there was no obvious degradation in power over 7000 hours. ? 2010 IEEE.Accession Number: 20104713410198 -
Record 198 of
Title:Generation of 10 GHz, 1.9 ps optical pulse train using semiconductor optical amplifier and silica-based highly nonlinear fiber
Author(s):Yan, S.Y.(1); Xie, X.P.(1,2); Hui, Z.Q.(1); Feng, H.(1); Zhao, W.(1)Source: Journal of Optics Volume: 12 Issue: 8 DOI: 10.1088/2040-8978/12/8/085401 Published: August 2010Abstract:We propose a simple approach to generate a high quality 10 GHz 1.9 ps optical pulse train using a semiconductor optical amplifier and silica-based highly nonlinear fiber. An optical pulse generator based on our proposed scheme is easy to set up with commercially available optical components. A 10 GHz, 1.9 ps optical pulse train is obtained with timing jitter as low as 60 fs over the frequency range 10 Hz-1 MHz. With a wavelength tunable CW laser, a wide wavelength tunable span can be achieved over the entire C band. The proposed optical pulse generator also can operate at different repetition rates from 3 to 10 GHz. ? 2010 IOP Publishing Ltd.Accession Number: 20104713405536 -
Record 199 of
Title:An improved centroid detection method based on higher moment for Shack-Hartmann wavefront sensor
Author(s):Xia, Ai-Li(1,2); Ma, Cai-Wen(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7850 Issue: DOI: 10.1117/12.870136 Published: 2010Abstract:The accuracy of the Shack-Hartmann wavefront sensor (SHWS) for measuring the distortion wavefront is mainly dependent upon the measurement accuracy of the centroid of the focal spot. Many methods have been presented to improve the accuracy of the wavefront centroid measurement by weakening the influence of various noises, such as the photo noise, the read-out noise, the background noise, unevenness and instability of the light source, etc. In general, these methods mainly use the first moment centroid algorithm to calculate the centroid in the whole sub-aperture. In this paper, we present an improved centroid measurement approach that calculate the centroid of the focal spot more precisely using the higher moment centroid method in an optimized detection window. Based on the improved method, the effects of various noises out of the optimized detection window are almost eliminated; furthermore, the noise influences in the optimized detection window are also weakened due to the more contributions of the focal spot intensity.The experimental results demonstrate that the precision and repeatability of focal spot centroid are more prominent than the results obtained via other commonly centroid methods. ? 2010 SPIE.Accession Number: 20110213573307 -
Record 200 of
Title:Packaging of high power semiconductor laser arrays using a novel macro-channel cooler
Author(s):Wang, Jingwei(1); Yuan, Zhenbang(2); Guo, Lu(2); Xiong, Lingling(1); Zhang, Yanxin(1); Peng, Chenhui(1); Li, Xiaoning(1); Liu, Xingsheng(1,2)Source: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010 Volume: Issue: DOI: 10.1109/ICEPT.2010.5582358 Published: 2010Abstract:High power semiconductor laser arrays have been widely used in many fields, such as pumping solid state laser aerospace, industry, medicine and display. For many applications, high power semiconductor lasers operating quasi-continuous wave (QCW) mode are demanded. For QCW laser, the output peak power is higher and average power is low. Therefore, the transient thermal density is very high. The most common method of removing the large amounts of waste heat in a semiconductor laser package is by using commercially-available copper micro-channel coolers (MCC). However, due to the coefficient of thermal expansion (CTE) mismatching between copper and laser chip, hardsolder cannot be directly used. On the other hand, indium solder has the problem of electro-thermal migration when the temperature grads were high in QCW mode. Furthermore, copper material is susceptible to erosion and corrosion. To overcome these hurdles in many applications, a novel macro channel cooler (MaCC) was presented in this work. The thermal behavior of MaCC-packaged high power semiconductor laser arrays in QCW mode was studied using finite element analysis (FEA). A high power of >250W QCW semiconductor laser array/bar using hard solder was fabricated. The performances of laser arrays, including output power, slope efficiency, threshold, conversion efficiency, spectral width, near field, lifetime etc. were characterized. The measured results indicated that the output power of a MaCC- packaged high power semiconductor laser array was very close to that of copper micro-channel cooler. Based on MaCC-packaged single laser array/bar, multiple-bar stack and two dimension area array lasers with output powers of several kilowatts and several tens of kilowatts were fabricated. ? 2010 IEEE.Accession Number: 20104713409991 -
Record 201 of
Title:Incoherent dark solitons splitting in LiNbO3:Fe crystal
Author(s):Zhang, Yuhong(1,2); Lu, Keqing(1); Long, Xuewen(1); Li, Kehao(1); Guo, Jianbang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7846 Issue: DOI: 10.1117/12.868757 Published: 2010Abstract:We observed experimentally one-dimensional even-number sequence of dark photovoltaic solitons in LiNbO3:Fe crystal without additional background illumination with spatially incoherent beam that contains a dark stripe generated from an amplitude jump in the center of the incoherent beam. In experiment, we found that the initial stripe width at the entrance face of the crystal is a key parameter for generating an even-number sequence of dark incoherent photovoltaic solitons. If the initial width of the dark stripe was small, only a Y-junction soliton pair was generated. As the initial width of the dark stripe was creased to 20.1μm, the stripe can split into an even-number sequence of soliton structure. The soliton pairs far away from the center had smaller width and less visibility. In addition, the separations between adjacent dark stripes became slightly smaller than that of the Y-junction dark solitons. In particular, when the input width in the entrance face of the crystal was 30.8μm, the diffractive beam in the output face of the crystal was no longer expanding its outer boundary, but shrank its width. ? 2010 SPIE.Accession Number: 20110213573251 -
Record 202 of
Title:An X-ray detector for X-ray pulsar based navigation and timing
Author(s):Zhao, Baosheng(1); Hu, Huijun(1,2); Sheng, Lizhi(1,2); Yan, Qiurong(1,2); Liu, Yongan(1); Chen, Ding(3)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: Issue: DOI: 10.1016/j.nima.2010.10.086 Published:Abstract:The pulse time of arrival (TOA) is a determinant parameter in the X-ray pulsar based navigation and timing. The measurement of TOA is implemented by super sensitive X-ray photon counting detector on the spacecraft. By comparing different kinds of detectors, an X-ray detector based MCP sensitive to X-ray energy band of 1-10 keV is proposed. The detector consists of input window, CsI photocathode, micro-channel plate (MCP) stack and a designed anode. The incident X-ray photons are detected and the pulse profile is reconstructed. By comparing the measurement pulse profile with the standard pulse profile of the X-ray pulsar source, the pulse TOA can be calculated. The experiment system, performance of the detector and results on the pulse profile are presented. ? 2010 Elsevier B.V. All rights reserved.Accession Number: IP51159530 -
Record 203 of
Title:Experimental study on an even-number sequence of solitons written in LiNbO3: Fe crystal
Author(s):Zhang, Yu-Hong(1,2); Lu, Ke-Qing(1); Zhang, Mei-Zhi(3); Sun, Ting(4)Source: Guangdianzi Jiguang/Journal of Optoelectronics Laser Volume: 21 Issue: 7 DOI: Published: July 2010Abstract:A dark stripe is generated when the partially spatially incoherent beam passes through amplitude mark. Based on bulk photovoltaic effect in LiNbO3: Fe crystal, one-dimensional even-number sequence of solitons with partially spatially incoherent beam is written in crystal without background illumination. When the width of the dark stripe is 13.4 μm, the stripe only splits into Y-junction solitons. However, the dark stripe splits into quadratic-solition when the width of the dark stripe is 20.1 μm. The experimental results reveal that an even-number sequence of dark photovoltaic soliton with partially spatially incoherent beam can be written in LiNbO3: Fe crystal without background illumination.Accession Number: 20103113111265 -
Record 204 of
Title:Study on spectral broadened characterization of cross phase modulation in photonic crystal fiber
Author(s):Hui, Zhan-Qiang(1,2); Zhang, Jian-Guo(1)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 30 Issue: 12 DOI: 10.3964/j.issn.1000-0593(2010)12-3295-07 Published: December 2010Abstract:Spectrum broadening induced by cross phase modulation (XPM) was investigated by exploiting the optical time-division multiplexing (OTDM) data signal and continue wave probe light co-propagation in dispersion flattened high nonlinear photonic crystal fiber (PCF). The effects of wavelength drift of probe lights, polarization mismatch, total power and power ration of pump and probe light on the spectrum broadening were analyzed. The results show that good XPM effects can be obtained in 36 nm wavelength range when the total power is higher than 23 dB, power ration of pump and probe light is appropriate and with identical polarization. Furthermore, polarization independent XPM effect can be achieved by using the remainder birefringence of the PCF with the pump state of polarization (SOP) aligned at 45° to the PCF principal axes. The obtained results in this paper would be helpful for research on ultrahigh-speed all optical signal processing devices exploiting the XPM in PCF for future photonics network.Accession Number: 20105113512274