可调谐窄带宽的负系数微波光子滤波器

Tunable narrow bandwidth negative coefficient microwave photonic filter

针对负系数微波光子滤波器很难用正系数的光学抽头来实现,提出了一款基于色散器件级联的可调谐、窄带宽、负系数微波光子滤波器。利用整形后的多波长光纤激光器的输出信号作为滤波器的抽头光源,将单模光纤与F-P光纤环级联作为延迟单元,实现滤波器的频率选择性。利用相位调制器和级联的色散器件共同作用,实现负系数的微波光子滤波器。实验得到了波长间隔为0.34 nm的多达37个激光信号的稳定输出,进而基于此实验结果仿真研究了F-P光纤环中C_2、C_3的耦合系数r、不同长度的可调谐光纤延迟线(TODL)和延迟单元中不同长度的单模光纤等参数对微波光子滤波器性能的影响。

A tunable, narrow bandwidth, negative coefficient microwave photonic filter based on cascaded dispersion devices was proposed, because the negative coefficient microwave photonic filter was very difficult to realize by the way of positive coefficient optical taps. The reshaped output signals of the multi-wavelength fiber laser were used as the tap of the filter. SMF and the F-P fiber ring were cascaded as a delay unit to realize the frequency selectivity of the filter. The negative coefficient was realized by a mixture of phase modulator and cascaded dispersion devices. As many as 37 stable laser signals with 0.34 nm wavelength interval were obtained by the experiment. And then based on the experiment results, the effects of coupling coefficient r of C2, Ca in the F-P fiber ring, different length TODL, and different length SMF in the delay unit etc. on the microwave photonic filters performance were simulated and studied.