In this paper, we present the evolution of reconfigurable optical add drop multiplexer（ROADM） technologies, and compare three main ROADM architectures available on the market today. Three archhectures include broadc...In this paper, we present the evolution of reconfigurable optical add drop multiplexer（ROADM） technologies, and compare three main ROADM architectures available on the market today. Three archhectures include broadcast-select and demux-switch-mux[and the integrated version planar lightwave circuit（PLC）] and wavelengths-selective switch.展开更多
The principle, structure and system of nonlinear liquid crystal optical signal amplifiers are described. Experimental results are theoretically analysed for optical signal amplifers. It shows that this type of the opt...The principle, structure and system of nonlinear liquid crystal optical signal amplifiers are described. Experimental results are theoretically analysed for optical signal amplifers. It shows that this type of the optical signal amplifiers are comprised of liquid crystal light sensitive medium which can receive a modulated signal optic wave and a pump wave, and can be applied to optical transmission systems.展开更多
In low-frequency elastic wave through-the-earth communication system,because of multipath transmission caused by characteristics of the layered earth,the time domain equalizer is different from other wireless communic...In low-frequency elastic wave through-the-earth communication system,because of multipath transmission caused by characteristics of the layered earth,the time domain equalizer is different from other wireless communication systems.A modified LMS algorithm of variable step size is proposed based on improvement of traditional LMS.On the base of principle and simulation analysis,the improved Least Mean Square(LMS)algorithm is analyzed and the performances are compared between the improved LMS algorithm and traditional LMS algorithm.In the improved algorithm,the contradiction between convergence speed and the steady-state error is considered at the same time.Therefore,the improved algorithm has good convergence properties and channel-tracking performance.展开更多
基金National High Technology Research and Development Programof China(2007AA03Z418)
文摘In this paper, we present the evolution of reconfigurable optical add drop multiplexer（ROADM） technologies, and compare three main ROADM architectures available on the market today. Three archhectures include broadcast-select and demux-switch-mux[and the integrated version planar lightwave circuit（PLC）] and wavelengths-selective switch.
文摘The principle, structure and system of nonlinear liquid crystal optical signal amplifiers are described. Experimental results are theoretically analysed for optical signal amplifers. It shows that this type of the optical signal amplifiers are comprised of liquid crystal light sensitive medium which can receive a modulated signal optic wave and a pump wave, and can be applied to optical transmission systems.
基金supported by the National Natural Science Foundation of China(No.61071016)
文摘In low-frequency elastic wave through-the-earth communication system,because of multipath transmission caused by characteristics of the layered earth,the time domain equalizer is different from other wireless communication systems.A modified LMS algorithm of variable step size is proposed based on improvement of traditional LMS.On the base of principle and simulation analysis,the improved Least Mean Square(LMS)algorithm is analyzed and the performances are compared between the improved LMS algorithm and traditional LMS algorithm.In the improved algorithm,the contradiction between convergence speed and the steady-state error is considered at the same time.Therefore,the improved algorithm has good convergence properties and channel-tracking performance.
