2015
2015
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Record 409 of
Title:Temporal cloak based on tunable optical delay and advance
Author(s):Zhou, Mingyang(1); Liu, Hongjun(1); Sun, Qibing(1); Huang, Nan(1); Wang, Zhaolu(1)Source: Optics Express Volume: 23 Issue: 5 DOI: 10.1364/OE.23.006543 Published: 2015Abstract:A temporal cloak scheme based on tunable optical delay and advance is theoretically proposed. An input optical signal is divided into two parts, and the front part is advanced while the rear part is delayed. A temporal gap which contains negligible optical energy is opened to hide events from observers, which can be closed by doing the inverse process. Different from the previous schemes that use continuous wave light, we use an optical data stream as the probe beam. Simulations have been done to investigate performance of the temporal cloak. The developed scheme can be applied in fiber-optical signal processing and secure communications. ? 2015 Optical Society of America.Accession Number: 20163302716115 -
Record 410 of
Title:Numerical simulation of surface-conduction electron-emitter
Author(s):Shen, Zhihua(1); Wang, Xiao(1); Wu, Shengli(1); Tian, Jinshou(2)Source: Proceedings of 2015 IEEE International Vacuum Electronics Conference, IVEC 2015 Volume: Issue: DOI: 10.1109/IVEC.2015.7223929 Published: August 25, 2015Abstract:In order to analyze the electron emission performance of SCE, the electric field distribution and electron trajectory are studied by simulation analysis with CST particle studio. Based on the simulation investigation, a SCE structure with better electron emission performance is obtained. It is expected that the simulation process and results are helpful for further development of SCE. ? 2015 IEEE.Accession Number: 20160300002195 -
Record 411 of
Title:Cavity linewidth narrowing by tunneling induced double dark resonances in triple quantum dot molecules
Author(s):Tian, Si-Cong(1); Wan, Ren-Gang(2); Li, Lian-He(1); Tong, Cun-Zhu(1); Ning, Yong-Qiang(1)Source: Optics Communications Volume: 334 Issue: DOI: 10.1016/j.optcom.2014.08.011 Published: January 1, 2015Abstract:A scheme for obtaining a tunable ultranarrow cavity transmission controlled by two tunneling in triple quantum dots system is proposed. In such system, the tunneling can induce double dark resonances, resulting in the appearance of two transparency windows. With the steep dispersion within the narrowed transparency windows, an ultranarrow transmission peak can be obtained, compared with that of double quantum dots system. Furthermore, by varying the energy splitting, the linewidth and the position of the ultranarrow transmission peak can be engineered. Because no coupling laser is required, the scheme proposed here is more convenient for future experiments and applications in optics, and may be useful in designing novel optoelectronic devices. ? 2014 Elsevier B.V.Accession Number: 20143718145415 -
Record 412 of
Title:Demonstration of 20Gb/s polarization-insensitive wavelength switching system for high-speed free-space optical network
Author(s):Qian, Feng-Chen(1,2,3); Ye, Ya-Lin(3); Wen, Yu(3); Duan, Tao(1); Feng, Huan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9679 Issue: DOI: 10.1117/12.2197788 Published: 2015Abstract:A 20Gb/s polarization-insensitive all-optical wavelength switching system for high-speed free-space optical communication (FSO) network is experimentally demonstrated All-optical wavelength conversion (AOWC) is implemented using four-wave mixing (FWM) by highly-nonlinear fiber (HNLF). In the experimental setup, a simple actively mode-locked fiber ring laser (AML-FRL) with repetition frequency from 1 to 15 GHz is used to generate eight 2.5Gb/s tributary signals, which are multiplexed into one 20Gb/s optical data stream. At the receiver, the 20 Gb/s OTDM data stream is demultiplexed down to 2.5 Gb/s via a polarization-insensitive FWM scheme. The whole space communication distance is over 10 meters in building hallway. The experimental results show that this system can stably run over 24 hours at 10-9 BER level, thus the proposed architecture can work at higher rate with wavelength-division multiplexing (WDM) and high order modulation schemes. ? 2015 SPIE.Accession Number: 20155201715844 -
Record 413 of
Title:Hundred micro-joules level femtosecond fiber laser amplification system
Author(s):Li, Feng(1); Yang, Zhi(1); Zhao, Wei(1); Li, Qianglong(1); Hu, Xiaohong(1); Yang, Xiaojun(1); Wang, Yishan(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 42 Issue: 12 DOI: 10.3788/CJL201542.1202005 Published: December 10, 2015Abstract:A fiber chirped pulse amplification system based on Yb3+ doped fibers is demonstrated. The seeder is a mode-locked fiber laser with semiconductor saturable absorber, the chirped pulse amplification technique is applied to stretch the 1030 nm pulse to several hundred picoseconds to be amplified. The single mode picosecond pulses with average power of 50 W and repetition rates of 211 kHz are achieved by using multistage pre-amplifier consisted with Yb3+ doped single mode fiber amplifier and double cladding fiber amplifier and the main amplifier with a large mode area rod-typed photonic crystal fiber as the laser gain material. Properly controlled the gain and the nonlinearity in every step of the amplification system, the influence of nonlinear effects are effectively suppressed on the pulse of time domain in high energy amplification. Laser pulses with pulse duration of 887 fs are generated by a reflective grating-pair compressor, corresponding to single pulse energy of 124 μJ and peak power of 139.8 MW. This experimental result of hundred micro joules level femtosecond laser based on fiber structure is firstly reported in China. ? 2015, Science Press. All right reserved.Accession Number: 20160601889084 -
Record 414 of
Title:All-optical signal processing technique for secure optical communication
Author(s):Qian, Feng-Chen(1,2,3); Su, Bing(1); Ye, Ya-Lin(1); Zhang, Qian(1); Lin, Shao-Feng(1); Duan, Tao(2); Duan, Jie(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9679 Issue: DOI: 10.1117/12.2199635 Published: 2015Abstract:Secure optical communication technologies are important means to solve the physical layer security for optical network. We present a scheme of secure optical communication system by all-optical signal processing technique. The scheme consists of three parts, as all-optical signal processing unit, optical key sequence generator, and synchronous control unit. In the paper, all-optical signal processing method is key technology using all-optical exclusive disjunction (XOR) gate based on optical cross-gain modulation effect, has advantages of wide dynamic range of input optical signal, simple structure and so on. All-optical XOR gate composed of two semiconductor optical amplifiers (SOA) is a symmetrical structure. By controlling injection current, input signal power, delay and filter bandwidth, the extinction ratio of XOR can be greater than 8dB. Finally, some performance parameters are calculated and the results are analyzed. The simulation and experimental results show that the proposed method can be achieved over 10Gbps optical signal encryption and decryption, which is simple, easy to implement, and error-free diffusion. ? 2015 SPIE.Accession Number: 20155201715854 -
Record 415 of
Title:A Single-Ring Absolute Encoder Subdivision Method
Author(s):Xiaogang, Su(1,2); Xiaodong, Hu(1); Zhang, Xiaodong(1)Source: Proceedings - 2015 7th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2015 Volume: Issue: DOI: 10.1109/ICMTMA.2015.21 Published: September 11, 2015Abstract:The basic working principle of single-ring absolute photoelectric shaft encoder is to use light-emitting diode as light source to illuminate the encoder, at the same time using linear CCD as photoelectric signal receiving device and subdivision device. So the essence of single ring absolute encoder subdivision technology is based on line array CCD subdivision technology. This paper proposes a linear CCD subdivision algorithm Based on polynomial interpolation method. By computing the center of the bar code to get value of accurate positioning, this calculates the center of the coded disc line. As a result of the existence of encoder's characterization error, this article adopts the average operation of multiple line center position to get the precise localization of encoder center line. So as to achieve the aim of improve the barcode location accuracy, and can realize in the application of engineering to achieve the precision of 1 ". ? 2015 IEEE.Accession Number: 20161102095258 -
Record 416 of
Title:Carrier-envelope phase measurement with linear optical sampling
Author(s):Li, Feitao(1,2); Hu, Hui(1,2,3); Zhao, Wei(1,2); Liu, Yuanshan(1,2)Source: IEEE Photonics Journal Volume: 7 Issue: 3 DOI: 10.1109/JPHOT.2015.2420688 Published: June 1, 2015Abstract:In the few-cycle pulses, the temporal evolution of the electric field sensitively depends on the carrier-envelope phase (CEP). The ability to measure and stabilize the CEP therefore becomes a crucial issue for all applications. However, few studies are focused on the measurement of CEP with coherent linear optical sampling. We propose an efficient method to measure the CEP of the frequency comb pulses by employing a high-resolution linear optical sampling technique. It is shown that constant chirp and pulsewidth of frequency comb pulses have negligible effect on the CEP measurement. ? 2009-2012 IEEE.Accession Number: 20151900820490 -
Record 417 of
Title:Two types of cavities for side-pumped Nd:YAG laser mode locked by semiconductor saturable absorber mirror
Author(s):Wang, J.L.(1); Jiang, Z.J.(1,2); Zhu, J.F.(1); Wang, Y.G.(2)Source: Optik Volume: 126 Issue: 23 DOI: 10.1016/j.ijleo.2015.08.251 Published: 2015Abstract:Two types of laser cavities for mode locked solid-state laser are designed based on transmission matrix ABCD of line-style resonator and z-style resonator. By adopting these two types of cavities, mode-locked Nd:YAG laser side-pumped by diode laser was realized with semiconductor saturable absorber mirror. The highest output power is 1.5 W with the repetition rate of 250 MHz in the line-style cavity. In the z-style cavity, the highest output power is 1 W, and the repetition rate is about 100 MHz with the pulse duration of 200 ps. ? 2015 Elsevier GmbH. All rights reserved.Accession Number: 20160101753646 -
Record 418 of
Title:Performance analysis of compressive ghost imaging based on different signal reconstruction techniques
Author(s):Kang, Yan(1); Yao, Yin-Ping(1); Kang, Zhi-Hua(2); Ma, Lin(2); Zhang, Tong-Yi(1)Source: Journal of the Optical Society of America A: Optics and Image Science, and Vision Volume: 32 Issue: 6 DOI: 10.1364/JOSAA.32.001063 Published: June 2015Abstract:We present different signal reconstruction techniques for implementation of compressive ghost imaging (CGI). The different techniques are validated on the data collected from ghost imaging with the pseudothermal light experimental system. Experiment results show that the technique based on total variance minimization gives high-quality reconstruction of the imaging object with less time consumption. The different performances among these reconstruction techniques and their parameter settings are also analyzed. The conclusion thus offers valuable information to promote the implementation of CGI in real applications. ? 2015 Optical Society of America.Accession Number: 20155101703322 -
Record 419 of
Title:Experiments of ghost imaging with pseudo-thermal light for remote sensing applications
Author(s):Kang, Zhihua(2); Ma, Lin(2); Kang, Yan(1); Yao, Yinping(1); Zhang, Tongyi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9674 Issue: DOI: 10.1117/12.2202795 Published: 2015Abstract:Based on previous researches, we construct a pseudo-thermal light ghost imaging system suited for remote imaging applications. By using pulsed pseudo-thermal light, the transmitted power is improved to ghost imaging long distant targets. By using imaging lens system, the path lengths of reference and signal light need not keep equal, as in lensless ghost imaging system, thus the transmitter, receiver, and correlator circuit can be integrated and keep compact. Furthermore, the revolution is improved by reducing the sizes of speckles. And the number of imaging frames is decreased (thus reduced the image-reconstruct time) and the signal-noise-ratio of ghost image is improved by compressed sensing. Based on the constructed experimental system, we implemented ghost imaging of a target at about 30m range. ? 2015 SPIE.Accession Number: 20155201719070 -
Record 420 of
Title:Image classification with densely sampled image windows and generalized adaptive multiple kernel learning
Author(s):Yan, Shengye(1); Xu, Xinxing(2); Xu, Dong(2); Lin, Stephen(3); Li, Xuelong(4)Source: IEEE Transactions on Cybernetics Volume: 45 Issue: 3 DOI: 10.1109/TCYB.2014.2326596 Published: March 1, 2015Abstract:We present a framework for image classification that extends beyond the window sampling of fixed spatial pyramids and is supported by a new learning algorithm. Based on the observation that fixed spatial pyramids sample a rather limited subset of the possible image windows, we propose a method that accounts for a comprehensive set of windows densely sampled over location, size, and aspect ratio. A concise high-level image feature is derived to effectively deal with this large set of windows, and this higher level of abstraction offers both efficient handling of the dense samples and reduced sensitivity to misalignment. In addition to dense window sampling, we introduce generalized adaptive p-norm multiple kernel learning (GA-MKL) to learn a robust classifier based on multiple base kernels constructed from the new image features and multiple sets of prelearned classifiers from other classes. With GA-MKL, multiple levels of image features are effectively fused, and information is shared among different classifiers. Extensive evaluation on benchmark datasets for object recognition (Caltech256 and Caltech101) and scene recognition (15Scenes) demonstrate that the proposed method outperforms the state-of-the-art under a broad range of settings. ? 2013 IEEE.Accession Number: 20150900579166