微波光子滤波器是一种能对微波信号实现滤波功能的微波光子子系统, 能够替代射频链路中的电子滤波器。作为微波光子滤波器的关键指标之一, 带宽会因为通带展宽效应而恶化。构建了一种基于宽谱光源、可调谐延时线、光谱处理器、色散元件的中心频率可调谐的微波光子滤波器, 分析了其中通带展宽效应的原理以及带宽和带宽延时积的关系, 提出了一种基于带宽延时积的带宽自动补偿方法。实验中, 滤波器带宽从687 MHz 补偿到 44 MHz, 中心频率可调谐到~70 GHz, Q值最高达到~1 600。因此该方法可有效补偿通带展宽效应, 对于实现高频窄带微波光子滤波器有参考意义。

Microwave photonic filters (MPF) are photonic sub-systems, which can filter microwave signal and work as electronic filters in the radio frequency link. As a key indicators of microwave photonic filters, the bandwidth is usually worsen due to passband broadening effect. A microwave photonic filter with tunable center frequency is built based on broadband optical source, tunable delay line, optical spectrum processor and dispersion module. Analysis of the principle of passband broadening effect and the relationship between the bandwidth and the bandwidth delay product is performed, then an iterative method is proposed to compensate the phenomenon. In the Experiment, the filter passband is reduced from 687 MHz to 44 MHz, and the center frequency is tunable up to ~70 GHz, the maximum Q value can reach ~1600. The method can effectively compensate for the passband broadening, and is of reference significance for the realization of microwave photonic filters with high frequency and narrowband.