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提出了一种基于色散位移光纤(DSF)的交叉相位调制(XPM)效应的超宽带(UWB)光学生成方法。该方法首先利用DSF的XPM效应实现高功率的高斯泵浦光对低功率的直流探测光的交叉相位调制,然后利用光纤布拉格光栅(FBG)对探测光进行鉴频,实现相位调制到强度调制的转换,从而获得单周期UWB信号。利用光子仿真软件对方案进行了仿真实验,得到了中心频率分别为7GHz和6.95GHz、相对带宽分别为143%和145%的UWB信号,验证了所提方法的可行性。同时,研究了输入信号脉冲宽度、FBG的反射率、鉴频器的类型对产生的单周期UWB脉冲信号波形和频谱的影响。仿真实验的结果表明,该方案对输入信号脉冲宽度不是过宽的情况下具有良好的容忍度,光学高斯带通滤波器、波分复用器和FBG等光滤波器均可作为鉴频器,采用FBG优点是可通过改变反射率灵活地调整产生的UWB脉冲信号的波形。
An ultra-wide band (UWB) optical generation method based on the cross-phase modulation (XPM) effect of Dispersion-Shifted Fiber (DSF) is proposed. In this method, the XPM effect of DSF is used to realize the cross-phase modulation of high-power Gaussian pump light to low-power direct-current probe light, and then the probe light is discriminated by fiber Bragg grating (FBG) to realize phase modulation to intensity modulation Conversion, to obtain single-cycle UWB signal. The photonic simulation software is used to simulate the scheme. The UWB signals with central frequencies of 7GHz and 6.95GHz and relative bandwidth of 143% and 145% respectively are obtained, which proves the feasibility of the proposed method. At the same time, the influence of input pulse width, FBG reflectivity and frequency discriminator on single UWB pulse waveform and frequency spectrum was studied. Simulation results show that this scheme has a good tolerance to the pulse width of the input signal is not too wide, optical filters such as optical Gaussian band-pass filter, wavelength division multiplexer and FBG can be used as a frequency discriminator, The advantage of FBG is that the waveform of the generated UWB pulse signal can be flexibly adjusted by changing the reflectivity.