提出级联直径蚀刻光纤法实现双波长滤波器的动态调节.采用耦合模理论和分段传输矩阵法进行理论推导和仿真,研究级联声光光栅可调双波长的直径蚀刻光纤滤波器,分析光纤蚀刻对声光光栅传输谱中旁瓣效应的抑制效果.结果表明光纤蚀刻法可以有效抑制旁瓣效应,旁瓣比从0.265下降到0.031;通过调节级联光栅的间隔保证双波长滤波器的两个对称谐振损耗峰的稳定性,间隔增加时左谐振波长峰值减小,右谐振波长峰值增大;双谐振峰的谐振波长由声频信号的频率和光纤级数调节,波长随周期变大而增大,在270 μm到282 μm内接近线性,当光纤段数增加时波长漂移量变大.

Cascaded diam-etched fiber was studied to realize the dynamic manipulation of dual-wavelength filter.Utilizing the coupled-mode theory and segmented transfer matrix method,the theoretical derivation and simulation calculation were carried out.A new type of tunable dual-wavelength filter was studied based on cascaded Acousto-Optic Gratings(AOGs) in diam-etched fiber.The side lobe suppression effect of diam-etched AOGs in the transmission spectra was analyzed.The results show that optical fiber etching method can effectively suppress the side lobe effect,the side lobe ratio can be decreased from 0.265 to 0.031;The dual-wavelength filter works symmetrically and efficiently with tunable frequency spacing by adjusting the fiber length.When the fiber length increases,left resonant wavelength peak decreases and right resonant wavelength peak increases.The wavelength of the dual wavelength filter tunable adjusted by the frequency of the acoustic signal and the number of segments of the fibers,the dual-wavelength increases with the acoustic wave,and approximately linearly between 270 μm to 282 μm,the wavelength shift enlarges with the number of fiber segments increasing.