提出了一种光子晶体光纤Lyot-Sagnac环切割宽带光源的中心频率连续可调的微波光子滤波器.用温敏液体（Cat.19340）对两段光子晶体光纤（长度为11.94 m和1.94 m）中心的一个大孔进行填充后嵌入Lyot-Sagnac环,仿真分析了不同填充占空比对Lyot-Sagnac环梳状谱周期和滤波器通带中心频率调谐范围的影响,结果表明：占空比越大,Lyot-Sagnac环的梳状谱周期越小,滤波器通带中心频率的调谐范围越大.在占空比最大温度为20℃和80℃时,两段光子晶体光纤的有效长度为10 m时,Lyot-Sagnac环的梳状谱周期分别为0.36 nm和0.26 nm;当两段光子晶体光纤的有效长度为13.88 m时,Lyot-Sagnac环的梳状谱周期分别是0.26 nm和0.19 nm.用该Lyot-Sagnac环对宽带光源进行切割,当温度在20℃到80℃之间变化时,通过调节环内的偏振控制器,多波长光源波长间隔可在0.19 nm~0.36 nm范围内连续可调,实现了滤波器通带中心频率在31.04 GHz~58.81 GHz范围内连续可调.

A microwave photonic filter based on photonic crystal fiber Lyot-Sagnac loop was presented,the filter′s center frequency can be continuously tunable. The length of the photonic crystal fiber is 11.94 m and 1.94 m,using the thermo-sensitive liquid of Cat.19340 to fill one big hole of the two photonic crystal fibers and then embed them into Lyot-Sagnac loop. Simulation analysis of the effect of different duty ratios to the period of comb spectra of Lyot-Sagnac loop and the tuning range of the passband center frequency of the filter. The result shows that the larger the duty ratio,the smaller the period of comb spectra of Lyot-Sagnac loop and the larger tuning range of the passband center frequency of the filter. In the case of the maximum duty ratio,when the effective length of the two photonic crystal fibers is 10 m,the simulation measured period of comb spectra of Lyot-Sagnac loop at the temperature of 20℃ and 80℃ is 0.36 nm and 0.26 nm,when the effective length is 13.88 m,the measured period of comb spectra is 0.26 nm and 0.19 nm respectively. Using the Lyot-Sagnac loop to slice the broadband light source,by adjusting the thermo-sensitive liquid′s temperature from 20℃ to 80℃ and the polarization controllers inside the ring,the wavelength of the light source can be tuned within the range of 0.19 nm~0.36 nm,the center frequency of the microwave photonic filter can be tuned continuously within the range of 31.04 GHz~58.81 GHz.