an output laser of an original pulse width in this invention pulse stretcher is implemented with a special dispersion management fiber that has a flat dispersion or a negative tod application_number US 19499808 A description referring to fig1 for a schematic diagram of a short pulse high energy fiber laser system that includes a laser seed 15 having an oscillator for generating a fiber based mode locking laser with original pulse duration the laser project from the oscillator of the seed laser 15 is projected into a laser stretcher 20 to stretch the laser pulse of this invention the stretcher 20 chirps laser pulse with stretched pulse width is projected into a series of laser amplifiers 25 to amplify the laser into higher energy the amplified laser is then projected into a pulse compressor 30 to re compress the pulse width of the laser to output a laser with original pulse width the pulse stretcher is implemented with a special dispersion management fiber that has a flat dispersion or a negative slope of dispersion versus wavelength fig2 is a diagram for illustrating the fiber dispersion index profile at different wavelength that may be implemented in the stretcher 20 of fig1 in an exemplary embodiment it is possible that a fiber with a flat dispersion may be implemented as a new fiber for the stretcher at a 1060 nm spectral band alternately the stretcher may be implemented with a fiber of a negative dispersion slope over the range of 1020 1090 nm by using a depressed cladding structure depending on the laser design in managing compensating tod with the nonlinear effects through the self phase modulation spm fibers with various dispersion and dispersion slope can be designed according to fig2 a fiber as a first new fiber embodiment of this.