Negative dispersion pulse widening optical fiber amplifying device

The invention discloses a negative dispersion pulse widening optical fiber amplifying device, which comprises a mode-locked laser, a negative dispersion unit, a primary amplifying unit, a secondary amplifying unit and an output unit, wherein the mode-locked laser generates seed light pulse; the negative dispersion unit is arranged at the emergent side of the seed light pulse of the mode-locked laser to widen the seed light pulse and enable the seed light pulse to have negative chirp; the primary amplifying unit receives the seed light pulse with the negative chirp, which is output by the negative dispersion unit, carries out primary amplification, and further carries out positive dispersion compensation on the negative chirp in the seed light pulse to shorten the seed light pulse; the secondary amplifying unit receives the seed light pulse output by the primary amplifying unit, carries out secondary amplification, and further carries out positive dispersion compensation on the negative chirp in the seed light pulse to shorten the seed light pulse; and the output unit is connected with the secondary amplifying unit and outputs the amplified seed light pulse. The invention makes the pulse of the output end of the optical fiber amplifier shortest via the negative dispersion widening, simplifies the system, reduces the loss, increases the pulse energy after the amplifier, and effectively reduces the cost.