A pulse configurable laser unit, PCLU, outputting uniform ultrashort pulses, comprising: a fiber pulse generator operating in a plurality of operational regimes to output a train of coherent uniform amplified giant chirped broadband pulses along a light path, wherein the fiber pulse generator is configured with a self-starting passively mode-locked fiber seed having two identical groups of optical elements which define a ring resonator, wherein the optical elements of each group include an Yb doped active fiber, fiber coil (16, 22) and narrow line filter (18, 24) the narrow line filters of respective groups being configured to have respective spectra overlapping one another, the elements being optically coupled to one another by a plurality of passive fibers.; a two-stage compressor including a static compressor, which is configured to compensate for a linear chirp component of each giant chirped broadband pulse, and a pulse shaper which is provided with a programmable spatial light modulator, SLM, to correct for a non-linear chirp component of the giant chirped broadband pulse, wherein the two-stage compressor outputs a train of transform limited, TL, ultrashort coherent pulses in each of the operational regimes of the fiber pulse laser generator; and one or more computers configured for executing a software for selectively retrieving a phase mask corresponding to a given operational regime from a library of phase masks, which is stored in a memory of the CPU, and operating the pulse shaper to apply the retrieved mask across to the programmable SLM of the pulse shaper so as to compensate for the nonlinear chirp component of the chirped pulse of the compressed TL ultrashort coherent pulses. a fiber pulse generator operating in a plurality of operational regimes to output a train of coherent uniform amplified giant chirped broadband pulses along a light path, wherein the fiber pulse generator is configured with a self-starting passively mode-locked fiber seed having two identical groups of optical elements which define a ring resonator, wherein the optical elements of each group include an Yb doped active fiber, fiber coil (16, 22) and narrow line filter (18, 24) the narrow line filters of respective groups being configured to have respective spectra overlapping one another, the elements being optically coupled to one another by a plurality of passive fibers.; a two-stage compressor including a static compressor, which is configured to compensate for a linear chirp component of each giant chirped broadband pulse, and a pulse shaper which is provided with a programmable spatial light modulator, SLM, to correct for a non-linear chirp component of the giant chirped broadband pulse, wherein the two-stage compressor outputs a train of transform limited, TL, ultrashort coherent pulses in each of the operational regimes of the fiber pulse laser generator; and a static compressor, which is configured to compensate for a linear chirp component of each giant chirped broadband pulse, and a pulse shaper which is provided with a programmable spatial light modulator, SLM, to correct for a non-linear chirp component of the giant chirped broadband pulse, wherein the two-stage compressor outputs a train of transform limited, TL, ultrashort coherent pulses in each of the operational regimes of the fiber pulse laser generator; and one or more computers configured for executing a software for selectively retrieving a phase mask corresponding to a given operational regime from a library of phase masks, which is stored in a memory of the CPU, and operating the pulse shaper to apply the retrieved mask across to the programmable SLM of the pulse shaper so as to compensate for the nonlinear chirp component of the chirped pulse of the compressed TL ultrashort coherent pulses.