Fiber laser, which is a direct current (MOPA) scheme, has perfect laser performance and good pulse shape control capability. Compared with the Q fiber laser, the pulse frequency and pulse width of the MOPA fiber laser are independent controlled, the two parameters can be adjusted to achieve a constant peak power output. In addition, by controlling the size of the seed source, the laser can be applied to a wider range of marking material, and the Q laser can not be changed into MOPA.