基于双平行调制器的微波光子链路周期性衰落抑制方法

The Suppression Method for Microwave Photonic Link Power Periodic Fading Based on DP-MZM

针对微波光子链路长距离传输过程中周期性衰落现象,提出了一种双边带调制的微波光子传输链路,来抑制色散效应导致的周期性衰落现象。通过双平行调制器实现载波抑制双边带调制以及对载波相位的调制,来调节色散效应引起的上下边带在光电转化后的射频信号的相位差,使其为同向叠加。同时,结合光纤中的受激布里渊散射效应反射的光信号,通过布里渊反射光强探测来获知需要调节的相位量,从而保证在变化的长距离传输中可以不出现射频信号的周期性变化。最后通过仿真实验,验证了链路周期性衰落的抑制效果。

Aiming at the periodic fading during the long-distance transmission of microwave photonic links,a microwave photonic transmission link based on double sideband modulation is proposed to suppress the periodic fading caused by the optical fiber dispersion effect.The phase difference caused by the dispersion effect between the lower and upper sidebands can be adjusted to ensure the coherent superposition of the converted RF signals,employing the DP-MZM(Dual Parallel Mach–Zehnder Modulator)to achieve the double sideband modulation and the phase control of carrier.Meanwhile,the light signal reflected by the excited Brillouin scattering effect in the fiber is combined with the Brillouin reflection light intensity detection to obtain the amount of phase to be adjusted,thus ensuring that no periodic changes in the RF signal can occur in the changing long-distance transmission.Finally,the suppression effect of link periodic fading is verified by simulation experiments.