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Multilayer-core fiber with a large mode area and a low bending loss

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Chinese Optics Letters 2016年第12期14卷 36-40页

作者：姜有超任国斌廉玉东刘昱刘怀清李海粟任文华简伟简水生 Key lab.of All Optical Network & Advanced telecommunication Network of EMC Beijing Jiaotong University Institute of Lightwave Technology Beijing Jiaotong University

We present a single-mode multilayer-core fiber with a large mode area（LMA） and a low bending loss in this Letter. A low equivalent core-cladding refractive index difference is achieved by exploiting the multilayer structure. The multilayer structure has a better bending performance than a traditional step-index core and this structure also contributes to realizing different curved refractive index profiles that have a better bending performance. An index trench is also introduced to dramatically reduce the bending loss. The experimental results show that, at a wavelength of 1550 nm, the mode area of the fabricated fiber is about 215.5 μm^2 and the bending loss is 0.58 dB/turn at a 10 mm bending radius. The LMA and excellent bending performance can be obtained simultaneously with the proposed fiber.

关键词： bending trench multilayer cladding radius refractive curved hundreds straight photonic

Adaptive Application Offloading Decision and Transmission Scheduling for Mobile Cloud Computing

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China Communications 2017年第3期14卷 169-181页

作者： Junyi Wang Jie Peng Yanheng Wei Didi Liu Jielin Fu Guangxi Key lab.of Wireless Wideband Communication & Signal Processing Guilin 541004 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200000 China School of telecommunication Engineering Xi'an University Xi'an 710049 China Sci. and Tech. on Info. Transmission and Dissemination in Communication Networks lab. Shijiazhuang 050000 China

Offloading application to cloud can augment mobile devices' computation capabilities for the emerging resource-hungry mobile application, however it can also consume both much time and energy for mobile device offloading application remotely to cloud. In this paper, we develop a newly adaptive application offloading decision-transmission scheduling scheme which can solve above problem efficiently. Specifically, we first propose an adaptive application offloading model which allows multiple target clouds coexisting. Second, based on Lyapunov optimization theory, a low complexity adaptive offloading decision-transmission scheduling scheme has been proposed. And the performance analysis is also given. Finally, simulation results show that,compared with that all applications are executed locally, mobile device can save 68.557% average execution time and 67.095% average energy consumption under situations.

关键词： mobile cloud computing application offloading decision transmission scheduling scheme Lyapunov optimization

High sensitivity D-shaped hole fiber temperature sensor based on surface plasmon resonance with liquid filling

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Photonics Research 2017年第2期5卷 103-107页

作者： SIJUN WENG LI PEI JIANSHUAI WANG TIGANG NING JING LI Key lab.of All Optical Network and Advanced telecommunication Network of Ministry of Education Institute of Lightwave TechnologyBeijing Jiaotong University

A high sensitivity D-shaped hole double-cladding fiber temperature sensor based on surface plasmon resonance(SPR)is designed and investigated by a full-vector finite element *** the D-shaped hole doublecladding fiber,the hollow D-section is coated with gold film and then injected in a high thermo-optic coefficient liquid to realize the high temperature sensitivity for the fiber SPR temperature *** numerical simulation results show that the peaking loss of the D-shaped hole double-cladding fiber SPR is hugely influenced by the distance between the D-shaped hole and fiber core and by the thickness of the gold film,but the temperature sensitivity is almost insensitive to the above *** the thermo-optic coefficient is -2.8×10^(-4)∕℃,the thickness of the gold film is 47 nm,and the distance between the D-shaped hole and fiber core is 5μm,the temperature sensitivity of the D-shaped hole fiber SPR sensor can reach to -3.635 nm∕℃.

关键词： High sensitivity D-shaped hole fiber temperature sensor based on surface plasmon resonance with liquid filling mode

Temperature-insensitive fiber Bragg grating strain sensor

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Optoelectronics Letters 2012年第6期8卷 414-417页

作者：周倩宁提纲裴丽李晶李超张婵 Key lab.of All Optical Network and Advanced telecommunication Network Ministry of EducationBeijing Jiaotong University

A fiber Bragg grating strain sensor,whose reflection bandwidth is insensitive to temperature,is *** cross-sec-tional area is designed to change *** axial stress,there is a linear relationship between stress and average *** results show that when temperature increases,reflection center wavelength shifts to longer wavelength,and there is a good linear relationship between center wavelength and *** stress increases,reflection center wavelength shifts to longer wavelength,and reflection bandwidth *** are good linear relationships between reflection center wavelength and stress as well as reflection bandwidth and stress.

关键词： Bandwidth Fiber Bragg gratings Sensors

Generation of microwave and millimeter-wave based on polarization scrambler and polarization maintaining fiber

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Optoelectronics Letters 2009年第4期5卷 281-283页

作者：史嫄嫄宁提纲李晶裴丽祁春慧 Key lab.of All Optical Network and Advanced telecommunication Network Ministry of EducationBeijing Jiaotong University

A new method is proposed to generate microwave and millimeter-wave by using polarization scrambler and polarization maintaining fiber(PMF),which is based on the coupling and the interaction between the two polarizations of the initial non-chirp Gaussian optical pulse in *** expressions of the microwave and millimeter-wave are derived by couple-mode ***,the feasibility is analyzed *** last,0-120 GHz microwave and millimeter-wave can be produced by adjusting system parameter or input pulse *** project is of great simplicity,stability and high export efficiency.

关键词：毫米波偏振波微波高斯光脉冲光纤护基使用维护持续时间

Performance Analysis of Optical Transmission Based on Seven Cores Fiber

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China Communications 2016年第9期13卷 113-120页

作者： Hang Zhou Fu Wang Borui Li Ming Tang Xiangjun Xin School of Electronic Engineering Beijing University of Posts and Telecommunication Wuhan National lab.for Optoelectronics(WNLO) Huazhong University of Sci&Tech(HUST)

This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most serious influence in multicore fiber transmission process. Before the experiment, the affecting factors of fiber crosstalk were analyzed through simulation, such as core space, bending radius, and fiber length. Combined with the simulation analysis, the design scheme of multicore fiber with low crosstalk was obtained. Before the fiber design, various factors of influence crosstalk such as the core- to-core distance, bending radius, fiber length and so on. Based on the simulation analysis, conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk. The space division multiplexing and wavelength division multiplexing technology, was adopted to conduct seven-core optical fiber transmission of *** crosstalk of adjacent core was suppressed to as low as 45dB / km, the attenuation of inner core was 0.24dB/ km, the outer cores＇ 0.32dB/km. Different bit error rate （BER） performances were also studied under different conditions, through reasonably designing the system to reduce the error rate, improve the performance of the system, and realize long distance and large capacity transmission with fiber.

关键词： multicore fiber crosstalk space division multiplexing

The Browsing Pattern and Review Model of Online Consumers Based on Large Data Analysis

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Chinese Journal of Electronics 2015年第1期24卷 58-64页

作者： NING Lianju WANG Haoyu FENG Xin DU Junping School of Economics and Management Beijing University of Posts and Telecommunications Beijing Key lab.of Intelligent telecommunication Software and Multimedia School of Computer ScienceBeijing University of Posts and Telecommunications

In the context of online shopping, commodity information and consumer reviews are main factors that will affect purchasing behavior. Started from the preference of commodity information browsing and the inherent property of online reviews, this paper focuses on the browsing data for statistical analysis and the interval distribution of consumer reviews based on the real data of360 buy which is the domestic large-scale B2 C commerce website in China. Researches find that commodity information browsing time distribution on Internet is fragment and can be depicted by the fat tail effect. It also demonstrated that user’s browsing patterns are related to the type of information and the displaying of the information,which means that the pieces of the picture and the length of the titles affecting the clicks rate. Reviews on the interval distribution can be depicted by the power-law function and there is a monotonically increasing relationship between power-exponent and the customers’ concerns with the corresponding commodity, the higher the exponent,the higher the degree of consumer attention. The finding obtained some basic rules of the browsing mode and review model, which is of important significance for future research.

关键词： Interval distribution Online consumer Browsing pattern Reviews model Trustworthiness.

Spectral characterization of fiber Bragg grating with etched fiber cladding

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Optoelectronics Letters 2012年第5期8卷 328-331页

作者：周倩宁提纲裴丽李超 Key lab.of All Optical Network and Advanced telecommunication Network Ministry of EducationBeijing Jiaotong University

A new method is presented to tune Bragg wavelength slightly by using hydrofluoric acid to etch fiber *** spectral characteristics before and after etching and the change properties of Bragg wavelength are *** modes are reduced during the etching ***-order cladding modes are converted into radiation modes,and energy of cladding modes is coupled to the *** the cladding radius decreases,the Bragg wavelength shifts to longer *** results show that this method can tune Bragg wavelength slightly,and the tunable range is 0.002-0.120 nm.

关键词： Etching Fiber Bragg gratings Hydrofluoric acid Spectrum analyzers Wavelength

IEEE 802.11 Distributed Coordination Function： Enhancement and Analysis

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Journal of Computer Science & Technology 2003年第5期18卷 607-614页

作者：邬海涛林宇程时端彭泳隆克平 Microsoft Research Asia (MSRA) National Key lab.of Switching Technology and telecommunication Networks Beijing University of Posts and telecommunications Beijing 100876 P.R. China

IEEE 802.11 Medium Access Control (MAC) is proposed to support asynchronousand time bounded delivery of radio packets. Distributed Coordination Function (DCF), which uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and binary slotted exponent ial backoff, is the basis of the 802.11 MAC. This paper proposes a throughput enhancement forDCF by adjusting the Contention Window (CW) setting scheme. Moreover, an analytical modelbased on Markov chain is introduced to compute the enhanced throughput. The accuracy of themodel and the enhancement of the proposed scheme are verified by elab.rate simulations.

关键词： IEEE802.11 MAC DCF 分布式调协函数 CSMA/CA