Investigation On The High Repetition Rate Picosecond Pulsed Fiber Laser And Fiber Amplifier

High-power and high-repetition-rate picosecond pulsed laser show great applications in micro-machining,laser ranging and high speed electro-optic sampling,how to improve the peak power and repetition rate pulsed laser have become a hot topic for researchers at home and abroad.In this paper,high-power and high-repetition-rate ultra-short pulsed laser is investigated both in theory and experiment.The contents are as follows.1.The basic theory involved in the ultra-short pulsed fiber laser are researched.An all-fiber picosecond pulsed seed laser is designed in the ring cavity,and the dissipative soliton is obtained in normal dispersion region,which shows the pulse width of 4.2 ps at the repetition rate of 19.2 MHz.Then,a picosecond pulsed laser with a linear cavity is constructed,which used a chirped fiber Bragg grating to provide a large anomalous dispersion for the cavity;finally,a conventional soliton mode-locking pulse with the repetition rate of 37.7 MHz and the pulse width of 4.5 ps is obtained.2.A four-stages Yb-doped fiber amplifier is constructed,and the heavily-doped gain fiber with a large core diameter is employed in the main amplification,which effectively suppress the nonlinear effects during amplified.Then the average output power of the seed laser is amplified to 50.4 W,corresponding to the peak power is325 k W,single-pulse energy is 2.63 ?J,and the spectrum is stretched from 3.6 nm only to 5 nm.3.A novel low-loss high-repetition-rate pulsed laser modulator based on optical coupler and time delay fiber is proposed,which overcome the limitation of the length of the cavity to repetition rate in conventional mode-locked fiber laser.That increase the repetition rate of the seed laser from 19.2 MHz to 1.2 GHz,it is characterized in that a 2×2 type coupler is utilized,which can enhance the coupling efficiency,and reduce the light loss during the whole process.