欧美亚洲福利,久久五月天色综合

2012

Record 373 of

Title:Widely tunable femtosecond optical parametric oscillator based on silicon-on-insulator waveguides

Author(s):Wen, Jin(1); Liu, Hongjun(1); Huang, Nan(1); Sun, Qibing(1); Zhao, Wei(1)
Source: Optics Express Volume: 20 Issue: 4 DOI: 10.1364/OE.20.003490 Published: February 13, 2012
Abstract:A femtosecond optical parametric oscillator (OPO) based on silicon-on-insulator (SOI) waveguide is proposed and analyzed numerically. By utilizing split-step Fourier method (SSFM), it is demonstrated that ultrawide tunable wavelength femtosecond pulse can be realized under the phase matching condition. Due to the interaction between nonlinearity and flexible dispersion design, the output signal wavelength can be tuned from 1645 to 1805 nm and the idler wavelength can be tuned from 1350 to 1456 nm. Moreover, the peak power of the output signal pulse exceeds 10 W from 1700 to 1770 nm with the pump peak power 50 W. The proposed OPO exhibits compact configuration and can find important applications in integrated broadband optical source. ? 2012 Optical Society of America.
Accession Number: 20120914810641
Record 374 of

Title:Comparison of end-pumped and multi-point pumped Yb3-doped gain guided and index antiguided fiber laser

Author(s):Wu, Jingwei(1); Zhou, Enyu(1); Yan, Kunlun(2); Wei, Wei(2,3); Peng, Bo(2,3)
Source: Optics and Laser Technology Volume: 44 Issue: 8 DOI: 10.1016/j.optlastec.2012.04.014 Published: November 2012
Abstract:End-pumped and multi-point pumped Yb3-doped gain guided and index antiguided (GGIAG) fiber laser are analyzed by solving the rate equations and 3-D thermal conduction equations. Simulation results show that the multi-point pumped scheme can provide lower operating temperature and better temperature uniformity. Meanwhile, fabrication complexity, loss resulted from pump point should be taken into consideration in the practical design. ? 2012 Published by Elsevier Ltd. All rights reserved.
Accession Number: 20122215079405
Record 375 of

Title:Temporal contrast enhancement of picosecond pulses based on phase-conjugate wave generation

Author(s):Liang, S.G.(1); Liu, H.J.(1); Huang, N.(1); Sun, Q.B.(1); Wang, Y.S.(1); Zhao, W.(1)
Source: Optics Letters Volume: 37 Issue: 2 DOI: 10.1364/OL.37.000241 Published: January 15, 2012
Abstract:A practical technique based on the phase-conjugate wave (PCW) generation is proposed to improve the temporal contrast of the picosecond pulses. Our theory predicts the temporal contrast of the picosecond pulses can be enhancedto about the cube of the temporal contrastof the input pulse via the PCW generation,in which the conversion efficiency from the incident pulse to the PCW is about 25%. In a proof-of-principle experiment, the temporal contrast of picosecond pulses was enhanced from 1.7 × 103 to 8.6 × 108 with the conversion efficiency of 10%. This technique is promising to effectively eliminate the background of the ultrashort and ultraintense laser pulses in the future. ? 2012 Optical Society of America.
Accession Number: 20120514729484
Record 376 of

Title:Prototype of an optical sampling oscilloscope with subpicosecond temporal resolution

Author(s):Liu, Yuanshan(1); Zhang, Jianguo(1); Tang, Dingkang(1); Zhao, Wei(1)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 32 Issue: 1 DOI: 10.3788/AOS201232.0107002 Published: January 2012
Abstract:Low timing-jitter, "σ"-type passively mode-locked fiber laser is used as a high-performance optical sampling pulse source, of which the operation stability is high and the repetition frequency is tunable. Then the generated sequence of ultrashort optical sampling pulses is launched together with a 80 Gb/s optical pulse signal under test into a 100 m-long highly nonlinear fiber (HNLF). The all-optical sampling of an optical signal under test is realized by utilizing the four-wave mixing (FWM) in a HNLF. Consequently, the waveform of a 80 Gb/s optical pulse signal with RZ format is precisely reproduced by a computer and is displayed on its screen by employing our developed software for digital signal processing and computer image processing, respectively. Moreover, the optical sampling oscilloscope prototype is used to measure the pulse waveform and pulse width at the output of a commercially available, actively mode-locked semiconductor laser which produces optical pulses of 1.8 ps width (measured by an autocorrelator) at the 10 GHz repetition frequency. In the experiment, the pulse width measured by this oscilloscope prototype system is 2.0 ps. It is clearly shown that our developed optical sampling oscilloscope prototype has a temporal resolution better than 900 fs.
Accession Number: 20120714766788
Record 377 of

Title:Influence of the wavefront mismatch, spatial chirp and multimode pump on the beam quality of OPCPA

Author(s):Sun, Qibing(1); Liu, Hongjun(1); Huang, Nan(1); Zhao, Wei(1)
Source: Journal of Modern Optics Volume: 59 Issue: 7 DOI: 10.1080/09500340.2011.648222 Published: April 10, 2012
Abstract:The beam quality and wavefront distribution of the optical parametric chirpedpulse amplification (OPCPA) frontend system of the petawatt laser has become a focus for research. The influence of wavefront mismatch, spatial chirp and multimode pump on the beam quality of OPCPA is numerically simulated and analyzed. It is shown that the beam quality and wavefront distribution becomes worse as the mismatch angle or the order of the spatial chirp increases. Meanwhile, it is also found that the beam quality and conversion efficiency of the amplified signal becomes worse as the transverse distribution of the pump laser descends. ? 2012 Copyright Taylor and Francis Group, LLC.
Accession Number: 20121414923159
Record 378 of

Title:High efficiency terahertz-wave photonic crystal fiber optical parametric oscillator

Author(s):Li, Shaopeng(1); Liu, Hongjun(1); Huang, Nan(1); Sun, Qibing(1); Li, Xuefeng(2)
Source: Applied Optics Volume: 51 Issue: 22 DOI: 10.1364/AO.51.005579 Published: August 1, 2012
Abstract:We theoretically propose phase matched terahertz (THz)-wave generation via degenerate four-wave mixing (FWM) in a fiber optical parametric oscillator (FOPO) with our newly designed photonic crystal fiber (PCF). Perfect phase matching is realized when we locate the pump wavelength in the normal group-velocity dispersion (GVD) regime. The generated THz-wave can be tuned from 4.7578 to 5.9015 THz by varying the pump wavelength. Moreover, peak power of 27.38 W at 5.9015 THz with conversion efficiency of 1.37% is realized when the pump peak power of 2000 W is at 4.675 μm in our FOPO. ? 2012 Optical Society of America.
Accession Number: 20123215323871
Record 379 of

Title:Simulation research of short range non-line-of-sight ultraviolet communication performance

Author(s):Tang, Yinan(1); Xie, Xiaoping(1); Zhao, Wei(1)
Source: 2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012 - Proceedings Volume: Issue: DOI: 10.1109/CECNet.2012.6201797 Published: 2012
Abstract:The non-line-of-sight single scattering channel model is significantly simplified by means of a closed-form expression. Based on such an approximation, the relationship between visibility and path loss of the ultraviolet communication system is analyzed, and the result is accordance with that obtained from original model. Moreover, the simulations of bit-error-rate indicate that path loss of communication channel has a lowest value and data rates have a highest value under fixed BER requirements when visibility is a critical point. The data rates which meet the different BER requirements are in the same order of magnitude at a given visibility and distance. ? 2012 IEEE.
Accession Number: 20122415104337
Record 380 of

Title:Effect of dehydration techniques on the fluorescence spectral features and OH absorption of heavy metals containing fluoride tellurite glasses

Author(s):Wang, P.F.(1); Li, W.N.(1); Peng, B.(1); Lu, M.(1)
Source: Journal of Non-Crystalline Solids Volume: 358 Issue: 4 DOI: 10.1016/j.jnoncrysol.2011.12.029 Published: February 15, 2012
Abstract:Heavy metal containing fluoride tellurite glasses were prepared by different dehydration techniques and the effects of dehydration techniques on fluorescence spectral features, OH content and volatilization of the glass compositions were systematically studied by means of fluorescence spectral measurements FTIR and energy-dispersive X-ray spectrometer. Experimental results indicated that different dehydration induced difference in actual compositions of the glasses that resulted in the variation of their fluorescence spectral features, and melting the glass frits in close environment with mechanical stirring and simultaneous bubbling dry O2 + CCl4 mixture in a O2-rich environment was much more effective to remove the OH groups in the glass matrix, through which an OH absorption coefficient and absorption concentration could be efficiently reduced to as low as 1.09 cm - 1 and 1.17 × 1019 cm- 3, respectively. The low OH content contributed to the increase in fluorescence lifetime, and resulted in the improvement of gain characteristic. The bubbling time of dry O2 + CCl4 mixture was optimized via OH absorption concentration investigation. ? 2011 Elsevier B.V.
Accession Number: 20120514724935
Record 381 of

Title:Latest progress and development trends of time-resolved streak camera technology

Author(s):Wang, Chao(1); Tian, Jinshou(1); Kang, Yifan(2); Wang, Tao(1)
Source: Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology Volume: 32 Issue: 7 DOI: 10.3969/j.issn.1672-7126.2012.07.21 Published: July 2012
Abstract:The latest progress in the time-resolved streak camera technologies was tentatively reviewed in a though provoking way. The discussions followed two outlines. One focused on the perspective of time-resolution and the innovations in the field of ultra-fast diagnostics in transient sciences were discussed. The o Ther centered on the technical applications and the road-map of time-resolved streak camera technologies was described, including many of the knowledge innovations of the two-color pump-probe atto-second streak camera, based on the diagnostic techniques of the conventional image-converter streak camera. The possible development trends and potential applications of the atto-second streak camera technologies in observing the ultra fast events occurred in the fascinating microscopic world were also discussed.
Accession Number: 20123715431575
Record 382 of

Title:Optimize and analysis of fiber optic gyroscope combination bracket based on redundancy design

Author(s):Liu, Ying(1,2); Zhao, Xiaodong(2); Li, Yan(3); Xu, Jintao(2)
Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 41 Issue: 6 DOI: Published: June 2012
Abstract:In view of the domestic research status of fiber optic gyroscope, a new combination of fiber optic gyroscopes bracket was designed based on the redundancy design scheme in order to meet the requirements of inertial navigation system which used the high accuracy and high reliability fiber optic gyroscopes. The Ansys finite element software was used to analyze the dynamics characteristic of the bracket. And the bracket was optimized based on the result of the modal analysis and frequency response analysis. After optimizing the bracket lighted 43%, and avoided resonance in the work frequency band of 0-2000 Hz, the acceleration response amplitude reduced significantly, and the response of deformation were less than 10-7, which could improve the dynamic characteristics of the bracket and laid a good foundation for raising the accuracy and reliability of inertial navigation system.
Accession Number: 20123715424644
Record 383 of

Title:Characteristic measurements of fiber Brillouin scattering using fiber Bragg grating based microwave-sweeping single sideband modulation

Author(s):Liu, Yu(1,2); Ren, Liyong(2); Hu, Manli(1); Liang, Jian(2); Han, Xu(2); Ma, Chengju(2)
Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 39 Issue: 1 DOI: 10.3788/CJL201239.0105002 Published: January 2012
Abstract:Single sideband modulation output is demonstrated by using of the fiber Bragg grating (FBG) and the Mach-Zehnder electro-optic modulator. Based on the microwave-sweeping single sideband modulation technique, a method to measure the characteristics of the fiber stimulated Brillouin scattering (SBS) is proposed. It can be used to measure the Brillouin frequency shift together with the Brillouin gain spectrum effectively. The properties of the stimulated Brillouin scattering in a 50 m photonic crystal fiber are measured, where the Brillouin frequency shift is 9.7443 GHz, the linewidth of the Brillouin gain spectrum is 22.472 MHz, and the Brillouin gain coefficient is 7.874×10-12 m/W, respectively.
Accession Number: 20120714767301
Record 384 of

Title:Double-mode refraction-type time-of-flight momentum (energy) mapping analyzer: Generalized theory

Author(s):Wang, Chao(1); Kang, Yifan(2); Tian, Jinshou(1)
Source: Optik Volume: 123 Issue: 24 DOI: 10.1016/j.ijleo.2011.10.034 Published: December 2012
Abstract:Generalized theory about the double-mode refraction-type time-of-flight momentum (energy) mapping analyzer is presented, which was inaccurately termed as reflection-type one and partially discussed in our previous material published in Optik (Ref. [9]). Key issues of operation modes classification of o mode and e mode, the specific condition and salient features for each of them, and magnetic field choosing are detailed, together with some corrections on that Optik material. The provided example verifies the theory. ? 2011 Elsevier GmbH.
Accession Number: 20124315603730