Production of tuneable picosecond light impulses in a visible spectral range

device to gain of light pulses, with an optical stretcher (2), in which stretched the light pulses of a pulsed laser light source (1) time are, and with an optically pumped gain fiber (3) in which the amplified light pulses and time-compressing, characterized in that the amplifier fiber (3) having a positive group velocity dispersion, in which the amplifier fiber (3) has non-linear optical properties, such that the optical Spectrum of the light pulses by utilizing nonlinear self-phase modulation during the amplification operation is widened.