宽调谐范围的单通带微波光子滤波器的研究

Study of an ultrawide tunable-range single-passband microwave photonic filter

基于相位调制技术和受激布里渊散射（SBS）效应,研制了可调谐单通带微波光子滤波器（MPF）。理论分析表明,通过引入频率间隔为受激布里渊频移量2倍的两个泵浦信号,使低频泵浦信号产生的损耗谱和高频泵浦信号产生的增益谱相抵消,所实现的滤波器的频率调谐范围为受激布里渊频移量的4倍,是单个泵浦信号时频率调谐范围的2倍,且随着泵浦光的数量增加滤波器的调谐范围呈倍数增长。实验测试了单泵浦条件下单通带可调谐滤波器的频率范围为0.8～18.2GHz,线宽为26MHz,带外抑制比为26dB,双泵浦时滤波器的频率调谐范围为0.8～31.1GHz。

A tunable single-passband microwave p hotonic filter is developed based on phase modulation and stimulated Brillouin s cattering.Theoretically,by introducing two pump signals whose frequency in terval equals 2times as large as the stimulated Brillouin frequency shift,the loss spectrum generated by the pump signal with low frequency is offse t by the gain spectrum of the pump signal with high frequency.As a result,a tuning range of 44GHz is achieved which is 2times as large as the range of a single pump signal.With the increas e of the number of pump light,the tuning range of the filter will grow exponentially.Under a si ngle pump and two pumps,we test the filter.The results are presented,which demonstrate a 0.8-18.2GHz and 0.8-31.1GHz measured tuning ranges,respectively,together with a band width of 26MHz and a out-of-band rejection of 26dB.