Abstract
Mode-locked fiber lasers have been extensively explored in recent years because of a variety of practical advantages. The new mode-locking mechanisms of self-similar and all normal dispersion fiber lasers increase the output pulse energy by more than one order of magnitude for the passively mode-locked femtosecond fiber lasers. In this thesis, we demonstrate an erbium-doped fiber oscillator with predominant normal group delay cavity dispersion (GDD) at 1.55 wavelength. A Fourier transform pulse shaper built into the cavity enables the central wavelength and bandwidth of the fiber oscillator to be widely tunable. An extra GDD introduced by the shaper effectively increases the pulse energy and reduces the nonlinear chirp of the output mode-locked pulse. The wave-breaking-free output pulse energy can be increased from 4.3 nJ to 8.9 nJ by adding an extra GDD of 0.178 ps2, limited by the available pump power of 320 mW. The pulse width and stability of the pulse train were thoroughly characterized by intensity autocorrelation, frequency-resolved optical gating, oscilloscope trace, and radio-frequency spectral analysis. Besides, supercontinuum generation from 1200 nm to 2400 nm was generated by a 15-m-long highly nonlinear fiber.