为了克服正抽头系数低通滤波的限制,满足光载无线通信(ROF)、无线通信等系统对带通滤波器的需要,提出了一种新的负系数带通微波光子滤波器结构。系统采用了一种偏振敏感的电吸收调制器,其横向电场(TE)和横向磁场(TM)方向上具有不同的调制系数,在小信号调制下仍为线性调制。通过旋转偏振控制单元的波片,改变其快轴与TE方向的夹角,可以得到任意偏振态的转换。当偏振控制单元由两个旋光方向相反的法拉第旋光片和一个1/2波片组合时实现了负系数滤波,和一个1/4波片组合时得到了正系数滤波。 In order to overcome the limitation of low-pass filter of positive tap coefficients and meet the requirement of band-pass filter in systems such as optical wireless communication (ROF) and wireless communication, a new negative-pass band-pass microwave photonic filter structure is proposed. The system uses a polarization-sensitive electroabsorption modulator with different modulation coefficients in the transverse electric field (TE) and transverse magnetic field (TM) directions, which is still linearly modulated with small signal modulation. By rotating the polarization control unit of the wave plate, changing the angle between its fast axis and the TE direction, any polarization state transition can be obtained. When the Polarization Control Unit consists of two Faraday rotators rotating in opposite directions and a 1/2 wave plate, the negative coefficient filter is realized, and the positive coefficient filter is obtained when combined with one 1/4 wave plate.