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Sun J.,Beijing Jiaotong University | Kang Z.,Beijing Jiaotong University | Wang J.,Science and Technology on Optical Radiation Laboratory | Liu C.,Beijing Jiaotong University | Jian S.,Beijing Jiaotong University
Optics Express | Year: 2014

A novel design, two-layer low-index trench fiber with parabolicprofile core, is proposed and investigated numerically in this paper. Based on scalar FD-BPM algorithm, the excellent performance over other types of structures and great potential in mode area enlargement are demonstrated. The effective mode area of our design (D = 100μm) is approximately 890 μm2. Both the high order mode (HOM) suppression and bending resistance of our design are better than that of Multi-Trench Fiber (MTF). The mode loss ratio and effective mode area are independent on the bending radius. Due to the circular symmetry of our proposed configuration design, the bending property is not varied with the changing of bending directions. © 2014 Optical Society of America. Source

Duan R.,Beihang University | Zhu X.-J.,Science and Technology on Optical Radiation Laboratory
Tuijin Jishu/Journal of Propulsion Technology | Year: 2015

A reaction mechanism involving intermediate reaction product HO2 was established for flow field simulation of afterburning of rocket plume. The mechanism was applied in CFD method to simulate the afterburning plume from an axisymmetric nozzle model at four altitudes. For comparison, a common mechanism without HO2 and a mechanism based on chemical equilibrium were used for the mentioned calculation. The results show that the hypothesis of chemical equilibrium was not appropriate for afterburning course. And compared with the common one, mechanism taking HO2 into account caused similar CO/CO2 mass fraction but higher temperature which had a maximum increasing of 100 K. As for the mass fraction of O/OH, there were huge disagreements, especially for the mass fraction of O whose value from the mechanism with HO2 various from 10% to 73% of that from the common mechanism, within the flight altitude from 5 km to 35 km. And it was concluded that HO2 was necessary to be involved into the simulation of afterburning plume. ©, 2015, Editorial Office of Journal of Propulsion Technology. All right reserved. Source

Wang J.,Science and Technology on Optical Radiation Laboratory
Multimedia, Communication and Computing Application - Proceedings of the International Conference on Multimedia, Communication and Computing Application, MCCA 2014 | Year: 2015

Due to the larger birefringence effect in highly nonlinear fibers (HNLF), it is able to observe a higher scattering efficiency of GAWBS. In this paper, we theoretically analyze the polarized and depolarized GAWBS induced by transverse acoustic mode in HNLF for the first time. We deduce the displacement function and scattering efficiency of GAWBS starting from the vibration function of transverse mode. The frequency of peak scattering efficiency in HNLF is higher than single-mode fiber (SMF-28), which appears at the frequency of nearly 470 MHz. The bandwidth of scattering in HNLF is about three times than that in SMF-28. The scattering efficiency of polarized GAWBS induced by R0m mode is bigger than that by TR2m mode, which is almost vanished at higher frequency. © 2015 Taylor & Francis Group, London. Source

Peng Y.,Science and Technology on Optical Radiation Laboratory | Lu H.,CAS Institute of Mechanics
Proceedings - 2013 IEEE International Conference on Green Computing and Communications and IEEE Internet of Things and IEEE Cyber, Physical and Social Computing, GreenCom-iThings-CPSCom 2013 | Year: 2013

In order to measure the error between the optical axis of infrared point source target simulator and the inner frame's central axis of three-axis turntable of five-axis flight motion simulator, a theoretical model was established to test the position of infrared point source target optical axis. The paper also analyzed the varieties of systematic errors and the testing principles and designed an experimental device which was used to test the optical axis of infrared point source target simulator. The experimental device which was fixed on the inner frame of three-axis turntable could measure the angle of the optical axis of infrared point source target simulator relative to the inner frame's central axis of turntable, thus it was able to carry out the testing of the optical axis relative to the inner frame's central axis of turntable. The precision of measuring angle is 0.2. Through the experiment, the angle of the optical axis of target relative to the inner frame's central axis of turntable is 1.0. © 2013 IEEE. Source

Zhang Z.,Harbin Institute of Technology | Xu Y.,Science and Technology on Optical Radiation Laboratory | Wu L.,Harbin Institute of Technology | Zhang Y.,Harbin Institute of Technology | And 2 more authors.
Optics Letters | Year: 2014

We present a photon counting range-intensity image strategy based on a single-photon detector in low-light level environments. In this Letter, a composite modulation method over the pulse sequence was used for the first time, to the best of our knowledge, which combined pulse-position modulation and pulse-intensity modulation. This composite modulation method could obtain range and intensity of the detected target at the same time. Besides, angle-angle information could be provided from the scanner or detector array. Thus, a range-intensity image of the target became feasible. For demonstrating this photon counting range-intensity image strategy, a proof-of-principle laboratory system was established. In low-light level environments, a range-intensity image of multiple similar targets was obtained successfully with the range accuracy of centimeter level and intensity error of 1%. Compared with the range image, a range-intensity image could better reorganize and identify similar targets. © 2014 Optical Society of America. Source

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