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利用直接电流调制光反馈半导体激光器产生了符合美国联邦通信委员会关于室内无线通信频谱限定的超宽带(UWB)微波信号.基于光反馈半导体激光器速率方程组,数值分析了偏置电流、反馈强度对混沌UWB脉冲信号的影响.研究表明,混沌UWB脉冲频谱的10dB带宽分别随着偏置电流的增大和反馈强度的增强而逐渐增加;中心频率分别随着偏置电流的增大和反馈强度的增强而逐渐增大.实验中,产生了中心频率为6.6GHz,10dB带宽为9.6GHz的混沌UWB信号.进一步,通过调节偏置电流和反馈强度,可实现混沌UWB信号的中心频率和10dB带宽的可调谐输出,实验结果和数值分析相符合.此外,实验产生的混沌UWB信号经过34.08km的光纤传输后,其频谱形状几乎没有发生变化,表明该方法所产生的混沌UWB信号对光纤色散有较大的容忍度.
UWB microwave signals that meet the definition of spectrum of indoor wireless communication by the Federal Communications Commission are generated by direct current modulated optical feedback semiconductor lasers.On the basis of optical feedback semiconductor laser rate equations, the bias current and the feedback intensity are analyzed numerically for chaos UWB pulse signal.The research shows that the 10dB bandwidth of chaotic UWB pulse spectrum increases with the increase of bias current and the feedback strength respectively.The center frequency gradually increases with the increase of bias current and the feedback intensity In the experiment, a chaotic UWB signal with a center frequency of 6.6GHz and a 10dB bandwidth of 9.6GHz was generated.Furthermore, by adjusting the bias current and the feedback intensity, a tunable output with a center frequency of chaotic UWB signal and a 10dB bandwidth , The experimental results are in good agreement with the numerical analysis.In addition, the chaotic UWB signal generated by the experiment has almost no change in spectral shape after passing through the 34.08 km optical fiber, indicating that the chaotic UWB signal generated by the method is more tolerant of fiber dispersion degree.