基于相位/强度调制的伪毫米波超宽带信号的光学辅助探测(英文)

Optics Assisted Envelope Detection of PMM-UWB Employing Phase/Intensity Modulation

针对伪毫米波超宽带信号脉冲宽度窄且信号强度低而不易探测的特点,本文提出了两种光学辅助包络探测方案.将伪毫米波超宽带信号调制到光载波上,利用光纤布喇格光栅带通滤波器滤出调制器输出的第一边带信号,通过光电探测器和低通滤波器便可以得到用于判决的伪毫米波超宽带信号的包络信息.数学推导和仿真分析了分别采用相位调制器和强度调制器对输出包络信号振幅的影响.研究结果表明:强度调制器需要偏置控制电路来稳定偏置点的位置,当强度调制器工作在最小传输点时,得到的包络信号幅值最大;相位调制器无需偏置控制电路,其输出信号包络的幅值等于使用强度调制器的系统可得到的最大值;使用相位调制器的系统较使用强制调制器的系统具有结构更简单和插入损耗更低的特点.

Pseudo millimeter wave ultra wide band signals have the characteristics of narrow pulse width,low signal strength,which make it is not easy to detect.To deal with such problem,two optics assisted envelope detection schemes were proposed.Firstly,a fiber Bragg grating was used for filtering one of the first sidebands at the output of the modulator,then the envelope of PMM-UWB signals for decision were obtained after photo-detection and low pass filter.Based on the method of mathematical derivation and numerical simulation,the effects of phase modulator or intensity modulator on the output envelope signal amplitude were analysed respectively.The results show that intensity modulator requires bias control to maintain a stable optical operating point,when the bias point of intensity modulator was switched to minimum transmission point,the maximum amplitude of envelope signals were acquired;phase modulator do not include the bias control,the amplitude of envelope in phase modulator is equal to the maximum amplitude in intensity modulator approximately.Compared with intensity modulation scheme,the phase modulation scheme has more advantages,such as simple structure,low insertion loss.