Tunable optical filter

The invention provides a tunable optical filter. The tunable optical filter includes a dual-core pigtail having an optical fiber exit end and an optical fiber receiving end. The adjustable optical filter further comprises an optical filtering path arranged between the optical fiber emitting end and the optical fiber receiving end. The optical filtering path comprises a collimating lens, a transmission-type grating and a wavelength tuning module. The optical filtering path further comprises a phase modulation element arranged between the dual-core tail fiber and the collimating lens, the phase modulation element is provided with a phase modulation surface, and the phase modulation surface is provided with a plurality of fluctuating parts to achieve a flat-topped filtering effect. The adjustable optical filter is simple in structure and low in manufacturing process difficulty. 本申请提供了一种可调光学滤波器。可调光学滤波器包括具有光纤出射端及光纤接收端的双芯尾纤。可调光学滤波器还包括设置于光纤出射端及光纤接收端之间的光学滤波路径。光学滤波路径包括一准直透镜、一透射式光栅、一波长调谐模块。光学滤波路径还包括设置于双芯尾纤与准直透镜之间的相位调制元