FIBER COMPRESSION SYSTEM FOR FREQUENCY MODULATED LASER PULSES BASED ON OPTICAL FIBER WITH A RECORDED

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The utility model relates to the field of laser physics, in particular to the generation of subpicosecond and femtosecond laser pulses with a high peak power value and a linear frequency modulation rate. The fiber compression system of frequency-modulated laser pulses based on optical fiber with a recorded refractive index lattice includes a radiation source - a master oscillator that provides the generation of spectrally limited pulses, an amplifier that is an active light guide doped with rare earth elements and having a normal dispersion of group velocities, a fiber with a recorded lattice of the refractive index with a smoothly increasing period, serially connected to an amplifier and passive optical fiber to cancel the frequency modulation and compression of frequency-modulated pulses. At the same time, the smoothly increasing period of the recorded lattices of the refractive index in the optical fiber leads to the fact that the effective value of the anomalous dispersion module of group velocities decreases exponentially along the length of the fiber, which makes it possible to achieve a steady propagation and reduce the duration of the frequency-modulated ultrashort laser pulses in the optical fiber with an increase in the speed of their frequency modulation. An important feature of the proposed scheme is the possibility of using light guides with a large fashion area, for example, tapered light guides, or light guides with a gradient profile of the refractive index and a modulo decreasing dispersion. This circumstance makes it possible to use fiber to form pulses with peak capacities of over 1 MW.