In wireless optical communication, effects of scintillation make average Bit Error Rate （BER） deteriorate. To improve system performance,PCCC （Parallel Concatenated Convolutional Code） encoding scheme is employed,...In wireless optical communication, effects of scintillation make average Bit Error Rate （BER） deteriorate. To improve system performance,PCCC （Parallel Concatenated Convolutional Code） encoding scheme is employed,and upper bound on the bit error rate is given by considering the effects of scintillation,APD noise and thermal noise. Simulation results show that the POOC encoding scheme can relieve turbulenceinduced intensity fluctuations and the system performance is improved remarkably.展开更多
In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure f...In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communication展开更多
Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-...Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-CATV co-network transmission systems are reported, followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fi ber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) an d different dispersion compensation schemes, (2) the impact of the complex on th e total nonlinear distortion induced by EDFA gain tilt and the light source. As a result , dispersion compensation optimal scheme and EDFA negative gain tilt are suggest ed as a solution to dispersion compensation and the nonlinear distortion self-c ompensation.展开更多
We propose the spectrum allocation and resource scheduling algorithms in cognitive point to multipoint (PMP) networks with rapid changes of spectrum opportunities and present a media access control (MAC) protocol base...We propose the spectrum allocation and resource scheduling algorithms in cognitive point to multipoint (PMP) networks with rapid changes of spectrum opportunities and present a media access control (MAC) protocol based on these algorithms. The objective of spectrum allocation is to make efficient use of the spectrum while maintaining the transceiver synchronization on frequency and time in the network. The objective of resource scheduling is to guarantee the quality of service (QoS) requirements of different kinds of connections and to minimize the total energy consumption in the network as well. By sensing only a small set of possible channels in each slot based on the state transition probability of each channel, our spectrum allocation algorithm achieves high spectrum efficiency in the network. The resource scheduling problem is divided into three sub problems and we derive optimal solutions to these problems by greedy algorithm and convex optimization. The simulation results show that our algorithm can make efficient use of the spectrum and the network resources at a cost of low computational complexity.展开更多
The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optica...The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optical beams.The dimensionless beam-width parameters and the inverses of the curvature radii for the wavefront of the two beams are given semi-analytically,and the transformations of the EGB with the rod lens are derived by use of the ABCD law of Gaussian optical beam.展开更多
The mechanism of γ-ray radiation induced absorption loss of the optical fiber in visible range is analyzed. According to the mechanism, the quantitative relation between loss in optical fiber and γ-ray cumulation do...The mechanism of γ-ray radiation induced absorption loss of the optical fiber in visible range is analyzed. According to the mechanism, the quantitative relation between loss in optical fiber and γ-ray cumulation dose is found by use of methods of solid physics and statistic physics. This quantitative relation is certified in terms of the results of radiation experiment.展开更多
文摘In wireless optical communication, effects of scintillation make average Bit Error Rate （BER） deteriorate. To improve system performance,PCCC （Parallel Concatenated Convolutional Code） encoding scheme is employed,and upper bound on the bit error rate is given by considering the effects of scintillation,APD noise and thermal noise. Simulation results show that the POOC encoding scheme can relieve turbulenceinduced intensity fluctuations and the system performance is improved remarkably.
文摘In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communication
文摘Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-CATV co-network transmission systems are reported, followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fi ber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) an d different dispersion compensation schemes, (2) the impact of the complex on th e total nonlinear distortion induced by EDFA gain tilt and the light source. As a result , dispersion compensation optimal scheme and EDFA negative gain tilt are suggest ed as a solution to dispersion compensation and the nonlinear distortion self-c ompensation.
基金Project (No. 2006AA01Z273) supported by the National Hi-TechResearch and Development Program (863) of China
文摘We propose the spectrum allocation and resource scheduling algorithms in cognitive point to multipoint (PMP) networks with rapid changes of spectrum opportunities and present a media access control (MAC) protocol based on these algorithms. The objective of spectrum allocation is to make efficient use of the spectrum while maintaining the transceiver synchronization on frequency and time in the network. The objective of resource scheduling is to guarantee the quality of service (QoS) requirements of different kinds of connections and to minimize the total energy consumption in the network as well. By sensing only a small set of possible channels in each slot based on the state transition probability of each channel, our spectrum allocation algorithm achieves high spectrum efficiency in the network. The resource scheduling problem is divided into three sub problems and we derive optimal solutions to these problems by greedy algorithm and convex optimization. The simulation results show that our algorithm can make efficient use of the spectrum and the network resources at a cost of low computational complexity.
文摘The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optical beams.The dimensionless beam-width parameters and the inverses of the curvature radii for the wavefront of the two beams are given semi-analytically,and the transformations of the EGB with the rod lens are derived by use of the ABCD law of Gaussian optical beam.
文摘The mechanism of γ-ray radiation induced absorption loss of the optical fiber in visible range is analyzed. According to the mechanism, the quantitative relation between loss in optical fiber and γ-ray cumulation dose is found by use of methods of solid physics and statistic physics. This quantitative relation is certified in terms of the results of radiation experiment.
