Ultrafast laser has the advantages of flexible design, short pulse width and high peak power, which has a very broad application prospect in the fields of micro-/nano-processing, biomedicine, national defense and military. In order to achieve ultrafast laser output, mode-locking technology is generally needed. To this end, researchers have proposed a variety of schemes. In 2003, Karen Intrachat and J. Nathan Kutz, Department of Applied Mathematics of University of Washington in USA, predicted theoretically that long-period fiber grating has pulse-shaping function, which can be used to construct ultrafast fiber lasers. In 2008, Abdullah S. Karar, Tom Smy and Alan L. Steele, department of electronics of Carlton University in Canada, conducted theoretical research on ultrafast fiber lasers with long-period fiber gratings. They found that this kind of laser can produce a variety of soliton pulses. However, there is a lack of experimental research on (ultra)-long-period fiber gratings as ultrafast optical devices by far.