基于受激布里渊散射效应的微波光子下变频系统

Microwave Photonic Down-Conversion System Based on Stimulated Brillouin Scattering Effect

提出一种基于受激布里渊散射效应的微波光子下变频系统。在此系统中,为了将高频率的射频信号转换成低频率的中频信号,引入一个本振信号并将其和射频信号分别通入到双平行马赫-曾德尔调制器两臂的两个子马赫-曾德尔调制器中,利用受激布里渊散射效应增益谱过滤出由射频信号与本振信号调制后产生的两个+1阶边带,之后这两个边带将会在光电探测器中拍频,得到中频信号。同时,该中频信号的相位可以通过调整双平行马赫-曾德尔调制器中母马赫-曾德尔调制器的偏置电压来改变。当下变频的射频信号频率为10.73 GHz时,最终可获得20~40 MHz范围内任意频率的信号,且其相位可在0°~360°之间线性变换。

This study presents a microwave photonic down-conversion system based on the stimulated Brillouin scattering. In this system, a local oscillator signal and radio frequency signal are introduced into two sub-Mach-Zehnder modulators of the dual-parallel Mach-Zehnder modulator to convert a high-frequency radio frequency signal to a intermediate frequency signal. Further, the gain spectrum of the stimulated Brillouin scattering effect is used to retain the two +1-order sidebands generated by the radio frequency and local oscillator signals. These two sidebands are then transmitted to a photodetector for beating, and an intermediate frequency signal is produced. Simultaneously, the phase of the intermediate frequency signal can be changed by adjusting the bias voltage of the parent Mach-Zehnder modulator in the dual-parallel Mach-Zehnder modulator. The frequency of the down-converted radio frequency signal is 10.73 GHz, which can be converted to a signal having any frequency in the range of 20-40 MHz and whose phase can be linearly transformed from 0° to 360°.