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Science china(information Sciences) 2011年第2期54卷 236-243页

作者： xu kun, yin jie, niu jian, sun xiaoqiang, wu jian & lin jintong key laboratory of information photonics and optical communications, ministry of education, beijing university of posts and telecommunications, beijing 100876, china key laboratory of information photonics and optical communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China

We propose and experimentally demonstrate the heterodyne mixing and polarization diversity tech- niques in radio over fiber (ROF) systems with the advantages of high sensitivity and dispersion endurance. The generation of 2.5 Gb/s optical DPSK and PSK signals, fiber propagation and wireless transmission over 15 GHz subcarrier are illustrated with very low sensitivity of -26 and -32 dBm, respectively. Moreover, based on the wireless polarization diversity techniques, we successfully performed the transmission of 1.3 Gb/s uncompressed high definition television (HDTV) signals with high quality.

关键词： radio over fiber heterodyne mixing polarization diversity

Efficient Mechanisms to Improve TCP Performance over OBS Networks

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china communications 2010年第2期7卷 87-91页

作者： Hong Xiaobin, Zhou Jun, wu jian, Guo Hongxiang, Zuo Yong, xu kun, lin jintong key laboratory of information photonics and optical communications, ministry of education Institute of optical communications and Optoelectronics, beijing university of posts and telecommunications, beijing 100876, china key laboratory of information photonics and optical communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Transmission Control Protocol (TCP) performance over optical Burst Switching (OBS) is experimentally investigated on an OBS network testbed, concluding that burst losses will lead to a significant drop in the available TCP bandwidth. Two mechanisms are introduced to improve TCP performance. One is concerning the burst assembly optimization and another is based on the novel assembly and scheduling mechanism to reduce the burst losses.

关键词： OBS ACK TCP burst loss probability scheduling algorithm

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Dynamically reconfigurable radio-over-fiber network with medium access control protocol to provide network access to train passengers

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Science china(information Sciences) 2013年第10期56卷 134-143页

作者： SHEN Xi xu kun sun xiaoqiang wu jian lin jintong State key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications

An innovative dynamically reconfgurable radio-over-fber(RoF)network equipped with an intelligent medium access control(MAC)protocol is proposed to provide broadband access to train passengers in railway high-speed mobile *** proposed RoF network architecture is based on a reconfgurable control station and remote access unit(RAU)that is equipped with a fxed flter and tunable *** proposed hybrid frequency-division multiplexing/time division multiple access(FDM/TDMA)based MAC protocol realizes failure detection/recovery and dynamic wavelength allocation to remote access *** result shows that with the proposed MAC protocol,the control station can detect failures and recover and dynamic wavelength allocation can increase the wavelength resource utilization to maintain network performance.

关键词： radio over fber medium access control protocol wavelength allocation failure detection failure recovery

Generation of 40 GHz phase stable optical short pulses using intensity modulator and two cascaded phase modulators

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Frontiers of Optoelectronics 2011年第3期4卷 292-297页

作者： Yu JI Yan LI Wei LI Xiaobing HONG Hongxiang GUO Yong ZUO kun xu jian wu jintong lin State key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications

Pulse sources based on lithium niobate modulators are very attractive for optical time division multiplexing(OTDM) transmission systems because the modulators are now commercially available, qualified for system use, and can operate up to very high speeds and over a wide wavelength range. In this paper, we describe the principles of operation and performance of the pulse source based on lithium niobate modulators. The pulse source is based on a Mach-Zehnder intensity modulator(IM) and two phase modulators(PMs). The continuouswave(CW) light is modulated in an IM and then strongly phase modulated in two cascaded PMs. The chirped pulses are subsequently compressed to desired width using dispersion compensation technology. This method has the advantage of acquiring larger chirp using normal PM rather than that special designed PM of very low Vπ. It can also generate shorter pulses than conventional methods incorporating only one PM driving by a radio frequency(RF) signal with the power larger than 1 W which may damage the device. Generation of 40 GHz optical pulses shorter than 2 ps is theoretically illustrated, simulated and experimentally verified. Experimental results show that 40 GHz phase stable optical pulses with pulse-width of 1.88 ps, extinction ratio(ER) larger than 20 dB, the timing jitter of 57 fs and signal-to-noise ratio(SNR) of 32.8 d B can be achieved. This is also a cavity-less pulse source whose timing jitter is determined only by the RF source rather than by the actively controlled cavity. In the experiment, the phase noise of the RF source we used is as low as – 98.13 dBc/Hz at a 10 kHz offset frequency which resulting very low timing jitter of generated *** pulses are then modulated at 40 Gbaud/s with an inphase/quadrature(I/Q) modulator and multiplexed to 160 Gbaud/s with less interference between each *** back-to-back demultiplexing by an electro-absorption modulator(EAM) to 40 Gbaud/s and demodulation by a delay interferometer(DI),

关键词： short pulse intensity modulator phase modulator pulse compression phase stable differential quadrature phase shift keying (DQPSK)

Enabling Technologies for Green Radio-over-Fiber Distributed Anten na System Based Wireless Sensor Network

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china communications 2011年第8期8卷 56-63页

作者：沈希徐坤伍剑林金桐 State key laboratory of information photonics and optical communications Beijing University of Posts and Telecommunications

Novel enabling technologies from physical layer to Medium Access Control (MAC) layer are proposed to provide energy efficient Radio-over-Fiber (RoF) Distributed Antenna System (DAS) based Wireless Sensor Networks (WSN). The power consumption performance of the network is evaluated in terms of the total network power consumption based on the proposed power consumption models from the physical layer. The results illustrate that for a given power consumption value, the tradeoff among the number of Remote Access Units (RAUs), the number of Multiple-Input Multiple-Output (MIMO) antennas and the number of hops must be taken into account. In order to efficiently reduce the total network power consumption, we also proposed a solution from the MAC layer using a sleep-aware MAC protocol, which can dynamically centralized control MIMO antennas to operate in a sleep mode. The proposed enabling technologies provide basis for selecting suitable RoF DAS based WSN and effectively reduce the power consumption.

关键词： RoF DAS WSN power consumption model medium control access protocol

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