| Abstract [eng] |
Temporal and Spectral Pulse Shaping for High Power Fiber Laser In this work subpicosecond pulse generation from SESAM mode-locked fiber oscillator is described. The management of pulse temporal and spectral properties in high power and high energy fiber amplifiers was investigated. The experimental realization of high contrast several hundred of femtosecond pulses from fiber chirped pulse amplification (FCPA) system was demonstrated. Numerical simulations and experimental results led to the development of fiber oscillator with temporal and spectral properties suitable for FCPA system. Effective spectral filtering technique of spectral sidebands was demonstrated. The optimization of chirped fiber Bragg grating (CFBG) reflection spectrum bandwidth in the fiber oscillator reduced the intensity of spectral sidebands and improved spectral contrast by a factor of 100. Near transform limited 1 ps pulses from fiber oscillator were stretched up to 430 ps duration, while their spectrum was broadened to 12.7 nm by self-phase modulation in a passive fiber. The compensation of gain narrowing in Yb doped all-in-fiber chirped pulse amplification system was investigated both numerically and experimentally. Pulse spectrum was broadened up to 37% at 1 μJ and up to 30% at 22 μJ pulse energy by spectral filtering technique using fiber Bragg grating filter with optimized transmission spectrum. Shorter pulses (approximately 12%) can potentially be obtained at the output of the laser system after the compensation. The laser radiation from the seed source was amplified in photonic crystal fiber amplifier up to 23.7 W average power. High contrast 270 fs duration and 20 μJ energy pulses were achieved after pulse compression. The impact of the nonlinear phase compensation for the output pulses was demonstrated. |
