2019
2019
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Record 289 of
Title:Ytterbium-doped Silica Fiber for High Power System:A Review of Research Progress and Development Trend
Author(s):Chen, Gui(1); Hou, Chao-Qi(2); Guo, Hai-Tao(2); Li, Jin-Yan(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 48 Issue: 11 DOI: 10.3788/gzxb20194811.1148012 Published: November 1, 2019Abstract:The ytterbium-doped silica fiber is one of the important basic element of fiber laser and amplifier system. The key to promote the further increase of fiber system power is the performance improvement of ytterbium-doped fibers. In this paper, the power increase and main challenge to power scaling of high power ytterbium-doped fiber laser system are reviewed, and the improvement scheme for the bottleneck problems of laser power climbing is briefly described. The research progresses in improving power restriction based on fiber fabrication technology, optical fiber material and fiber structural design are described in detail. Furthermore, the future research and development tendency of ytterbium-doped silica fiber are prospected. ? 2019, Science Press. All right reserved.Accession Number: 20195307948761 -
Record 290 of
Title:Is it possible to enlarge the trapping range of optical tweezers via a single beam?
Author(s):Li, X.Z.(1); Ma, H.X.(1); Zhang, H.(1); Tang, M.M.(1); Li, H.H.(1); Tang, J.(2); Wang, Y.S.(2)Source: Applied Physics Letters Volume: 114 Issue: 8 DOI: 10.1063/1.5083108 Published: February 25, 2019Abstract:For optical tweezers, a tiny focal spot of the trapping beam is necessary for providing sufficient intensity-gradient force. This condition results in a limited small trapping range to guarantee stable trapping of the particle. Exploiting structured light, i.e., an optical vortex beam, the trapping range can be enlarged by adjusting its doughnut ring diameter. However, the trapped particle scarcely remains static due to the optical spanner action of the orbital angular momentum of the vortex beam. To enlarge the trapping range and simultaneously ensure stable trapping, we propose a beam, referred to as a mirror-symmetric optical vortex beam (MOV). Essentially, MOV is constructed by using two opposite optical spanners and a pair of static optical tweezers. The optical spanners attract the particle to the site of the static optical tweezers, which realizes long-range optical trapping. Through detailed force-field analysis, it is found that MOV could perform these setting functions. In experiments, yeast cells are manipulated in a long range of ～25 μm, which is 3 times longer than that of the Gaussian beam. Further, the trapping range is easily adjusted by changing a parameter as desired. This technique provides versatile optical tweezers, which will facilitate potential applications for particle manipulation. ? 2019 Author(s).Accession Number: 20191006585488 -
Record 291 of
Title:Ultra-thin carbon fiber mirrors: nickel plated, optical fabrication and thermal deformation test
Author(s):Xu, Liang(1); Xie, Yongjie(1); Wang, Yongjie(1); Ding, Jiaoteng(1); Ma, Zhen(1); Fan, Xuewu(1)Source: Optik Volume: 176 Issue: DOI: 10.1016/j.ijleo.2018.09.086 Published: January 2019Abstract:The aperture of space remote sensing camera is increasing, and the demand for lighter weight is getting higher and higher. With the advancement of active optics, the thickness of optical components has gradually grown to light and thin. It is extremely difficult to develop ultrathin mirrors using brittle materials such as traditional optical glass and silicon carbide. Due to advantages such as low density, high specific stiffness, low thermal expansion coefficient, toughness, and additive rapid manufacturing properties, carbon fiber reinforced plastic (CFRP) is one of potential applications for large-diameter ultra-thin mirrors. However, the carbon fiber composite material is a two-phase material that cannot be used as optical surface and must be surface-modified. In this paper, the surface modification of CFRP substrate was carried out by chemical nickel plating and nickel electroplating. The modified nickel layer covers all surfaces of CFRP substrate, and nickel layers satisfying the thickness, bonding force, and internal stress requirements. A Φ100 mm aperture ultra-thin carbon fiber mirror developed, after optical fabricating, its surface accuracy RMS is better than λ/15. Thermal deformation analysis and test show that the thermal deformation of ultra-thin carbon fiber mirrors is mainly manifested by the change of radius of curvature, which is caused by the thickness error of the nickel layer on the front and rear faces. In addition, although thermal deformation caused by the lamination angle error of CFRP substrate is relatively small in value, it should still be given enough attention, because the astigmatic error produced is hard to eliminate. ? 2018 Elsevier GmbHAccession Number: 20183905870529 -
Record 292 of
Title:Streaking of argon L-shell auger emissions with > 250 eV attosecond X-ray pulses
Author(s):Han, Seunghwoi(1); Xu, Peng(2); Wang, Yishan(2); Zhao, Kun(3); Chang, Zenghu(1)Source: Optics InfoBase Conference Papers Volume: Part F128-CLEO_QELS 2019 Issue: DOI: 10.1364/CLEO-QELS.2019.FF3C.4 Published: 2019Abstract:We investigate the Argon Auger decay using isolated attosecond X-ray pulses reach the Carbon K-edge. A home-built electron spectrometer resolves and measures lifetimes of L-shell vacancies of Argon in pump-probe experiment. ? 2019 The Author(s).Accession Number: 20192707140283 -
Record 293 of
Title:All-optical phase regeneration in free-space optical communication networks
Author(s):Sun, Yue(1,2); Huang, Xinning(1); Wen, Yu(3); Xie, Xiaoping(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 48 Issue: 9 DOI: 10.3788/IRLA201948.0918003 Published: September 25, 2019Abstract:Based on the application requirements of high-speed optical data multi-hop transmission in free-space optical communication network, and aiming at the problem that the signal quality of phasemodulated laser link after long -distance transmission in space degraded, the all-optical phase regeneration for binary phase shift keying modulated high-rate signal, based on the phase-sensitive fourwave mixing (FWM) effect in high nonlinear fiber (HNLF) was proposed. Numerical analysis with Matlab was carried out to find out the factors affecting the regeneration results. Then based on the OptiSystem simulation tool, an all-optical phase regeneration system for a 10 Gbit/s differential phase shift keying (DPSK) optical signal was constructed. Combining the link budget for geosynchronous (GEO) to optical ground station (OGS), system performance in three situations, namely back-to-back (B2B), phase-noised as well as noised-and-regenerated, were compared and analyzed. Simulation results and numerical analysis results show that compared with the system without regeneration after degradation, the bit-error-ratio (BER) of the noised-and-regenerated system improves nearly 4 orders of magnitude, while the output optical signal-to-noise-ratio (OSNR) increases nearly 3 dB. The results indicate that all-optical phase regeneration in free-space optical communication system can achieve all-optical phase regeneration of phase modulation signal. It can effectively promote the performance of spatial coherent laser communication system and can be used in the all -optical data relay of high speed free -space optical communication network relay nodes. ? 2019, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20194507622607 -
Record 294 of
Title:A dual-wavelength Q-switched fiber laser based on reduced graphene oxides
Author(s):Su, Yulong(1,2,3); Huang, Xinning(1,3); Hu, Hui(1); Wen, Yu(4); Xie, Xiaoping(1,3); Si, Jinhai(2); Wang, Yishan(1,3); Zhao, Wei(1,3)Source: Laser Physics Volume: 29 Issue: 6 DOI: 10.1088/1555-6611/ab0d12 Published: April 11, 2019Abstract:This report demonstrates a dual-wavelength stable Q-switched Er-doped fiber (EDF) laser with a reduced graphene oxide (rGO)-based saturable absorber. The rGO is prepared by depositing the graphene oxide on fluorine mica (FM) using a thermal reduction method. The modulation depth and saturable intensity of rGO/FM are measured to be 5.8% and 73.6 MW cm-2. By employing the rGO/FM film in the EDF laser cavity, stable dual-wavelength Q-switching operation is achieved. The two wavelength peaks locate at 1531.84 nm and 1558.14 nm. The shortest pulse duration is 1.83 μs. The maximum output power is measured to be 14.65 mW, corresponding to the maximum single pulse energy of 154.34 nJ. The experimental results evidently show that the rGO is a promising type of nonlinear material. ? 2019 Astro Ltd.Accession Number: 20192607088941 -
Record 295 of
Title:Simultaneous polarization separation and switching for 100-Gbps DP-QPSK signals in backbone networks
Author(s):Su, Yu-Long(1,2,3); Feng, Huan(1,3); Hu, Hui(1,3); Wang, Wei(1,3); Duan, Tao(1,3); Wang, Yi-Shan(1); Si, Jin-Hai(2); Xie, Xiao-Ping(1); Yang, He-Ning(1,2,3); Huang, Xin-Ning(1,3)Source: Chinese Physics B Volume: 28 Issue: 2 DOI: 10.1088/1674-1056/28/2/024216 Published: 2019Abstract:We propose a novel scheme of simultaneous polarization separation and switching, based on the orthogonally-polarized four-wave mixing (FWM) effect, for ultra-high-speed polarization multiplexing (Pol-MUX) fiber networks such as 100-Gbps and 400-Gbps backbone networks. We use theoretical and experimental analysis of the vector theory of FWM to successfully achieve polarization separation and all-optical switching by utilizing a 100-Gbps dual polarization-quadrature phase shift keying (DP-QPSK) signal and two orthogonally-polarized pumps. Both of the polarization-separated QPSK signals have clear constellation diagrams, with root mean square (RMS) error vector magnitudes (EVMs) of 14.32% and 14.11% respectively. The wavelengths of idlers can be created at 30 different wavelengths, which are consistent with International Telecommunication Union-Telecommunication (ITU-T) wavelengths, by flexibly changing the wavelength of the pump light. Moreover, the idlers that have distinct wavelengths have power distributed in a range from -10 dBm to -15 dBm, which can support error-free transmission. The power penaltyis 5 dB lower than that of back-to-back (BTB) signal for both the X- and Y-polarization components measured at a bit error ratio (BER) of 3.8×10-3. Our experimental results indicate that this scheme has promising applications in future backbone networks. ? 2019 Chinese Physical Society and IOP Publishing Ltd.Accession Number: 20191006613602 -
Record 296 of
Title:An efficient framework for unsupervised feature selection
Author(s):Zhang, Han(1); Zhang, Rui(2); Nie, Feiping(1); Li, Xuelong(1)Source: Neurocomputing Volume: 366 Issue: DOI: 10.1016/j.neucom.2019.07.020 Published: 13 November 2019Abstract:In these years, the task of fast unsupervised feature selection attracts much attentions with the increasing number of data collected from the physical world. To speed up the running time of algorithms, the bipartite graph theory has been applied in many large-scale tasks, including fast clustering, fast feature extraction, etc. Inspired by this, we present a novel bipartite graph based fast feature selection approach named Efficient Unsupervised Feature Selection (EUFS). Compared to the existing methods focusing on the same topic, EUFS is advanced in two aspects: (1) we learn a high-quality discrete indicator matrix for these unlabelled data by virtue of bipartite graph based spectral clustering, instead of obtaining an implicit cluster structure matrix; (2) we learn a row-sparse matrix for evaluating features via a generalized uncorrelated regression model supervised by the achieved indicator matrix, which succeeds in exploring the discriminative and uncorrelated features. Correspondingly, the features selected by our model could achieve an excellent clustering or classification performance while maintaining a low computational complexity. Experimentally, the results of EUFS compared to five state-of-the-art algorithms and one baseline on ten benchmark datasets verifies its efficiency and superiority. ? 2019Accession Number: 20193207289152 -
Record 297 of
Title:Characterization and Properties of Large-core Fluorine-doped Fibers Based on Depressed Inner Cladding Design
Author(s):She, Sheng-Fei(1,2); Liu, Bo(1,3); Chang, Chang(1,2); Xu, Yan-Tao(1); Xiao, Xu-Sheng(1); Gao, Song(1); Zhang, Yan(1); Li, Yi-Zhao(1); Hou, Chao-Qi(1); Guo, Hai-Tao(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 48 Issue: 11 DOI: 10.3788/gzxb20194811.1148013 Published: November 1, 2019Abstract:The surface morphology and microstructure of fiber preform taper zones and fibers with different fluorine content and waveguide structure were characterized by stereomicroscopy, scanning electron microscopy and Raman spectroscopy. The loss and laser transmission efficiency of large-core fibers with fluorine-doped cladding were analyzed by fiber analysis system and self-made output laser probe. The results show that the fluorine volatilization phenomenon becomes more obvious with the increase of fluorine content. As a result, the surface defects of traditional large-core fibers with fluorine-doped cladding increase, such as cracks and pits. Simultaneously, the fiber loss increases slightly and the laser transmission efficiency decreases. Moreover, the fluorine volatilization and crystallization during the fabrication process of large-core fibers with fluorine-doped cladding are effectively suppressed through subsidence fluorine-doped inner cladding design. Thus, the fiber loss at 1 200 nm is 3.99 dB/km, and the laser transmission efficiency at 2 μm of flat and spherical fibers is 88.9% and 88.4%, respectively. It can be obviously seen that its property is better than that of traditional fibers. ? 2019, Science Press. All right reserved.Accession Number: 20195307948396 -
Record 298 of
Title:Modeling and simulation of a mid-IR 4.3 μm Raman laser in chalcogenide glass fibers
Author(s):Peng, Xuefeng(1,2); Zhang, Peiqing(2); Wang, Xunsi(2); Guo, Haitao(3); Wang, Pengfei(4); Dai, Shixun(2)Source: OSA Continuum Volume: 2 Issue: 8 DOI: 10.1364/OSAC.2.002281 Published: August 15, 2019Abstract:Raman lasers based on mid-infrared (IR) fibers that operate at the 3-5 μm atmospheric transparency windows are attractive sources for many important applications. In this work, a Raman laser operating in the mid-IR range at 4.3 μm based on an As2Se3 fiber pumped by a 3.92 μm fiber laser has been designed and systematically optimized. The influences of pump power, fiber length, and output coupling efficiency on laser performance are investigated. Simulation results show that a fiber length of 0.75-1.3 m and an output coupler reflectivity of 89%-98% could obtain the optimized output power. The maximum output power of 0.269 W was obtained at a pump power of 1.5 W. The simulated result can be used for theoretical guidance and design optimization of practical chalcogenide fiber Raman lasers. ? 2019 Optical Society of America under the terms of the OSA Open Access Publishing AgreementAccession Number: 20203609124827 -
Record 299 of
Title:An assembly method for large-aperture laser beam reduction system
Author(s):Zheng, Xiang Ke(1); Kang, Shi Fa(1); Fu, Xi Hong(1); Li, Hua(1); Duan, Ya Xuan(1); Li, Hong Guang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11338 Issue: DOI: 10.1117/12.2544149 Published: 2019Abstract:The paper presents a method based on the principle of auto-collimating to assemble the large-aperture laser beam reduction system. The method solves the problem of using fiber laser, plane mirror and Hartman wavefront sensor to realize the precision assembling of the large-aperture laser beam reduction system in the absence of large-diameter standard light source. Using the method, The large-aperture laser beam reduction system is successfully assembled in the big science project. And the technical index of the system is tested and the uncertainty is analyzed. The near field modulation degree is 1.03, the contrast is 0.025, the wavefront distortion is 0.476λ(λ=1053nm), and the system meets the requirements of the engineering index. ? 2019 copyright SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20200308056962 -
Record 300 of
Title:Mirrors fabricated with CFRP composites by replication technology
Author(s):Wu, XiaoGe(1); Wang, YongJie(1); Xu, Liang(1); Ma, Zhen(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10837 Issue: DOI: 10.1117/12.2504928 Published: 2019Abstract:To realize ultra-lightweight ratio, mirrors were fabricated with CFRP (carbon fiber reinforced plastic composites) by replication technology. The replication technology was aimed to improve surface accuracy. Though replication technique, the surface accuracy was improved to 0.098 λ (λ=632.8nm, RMS), and the roughness of 1.9 nm (Ra) can be achieved. The CFRP mirror presented poor dimension stability, the surface accuracy increased gradually in air. In order to solve this problem, a polymer coating was carried on mirror surface. The polymer coating exhibited better dimension stability, the surface accuracy can be maintained under 0.15 λ for more than 200 days. ? 2019 SPIE.Accession Number: 20190506432486