Generation of ultrafast laser with 11 MW peak power from a gain-managed nonlinear tapered fiber amplifier

A gain-managed nonlinear (GMN) tapered fiber amplifier with a monolithic configuration is experimentally demonstrated. Both the forward and backward pumping scheme were investigated, and the results indicate that the latter is advantageous in suppressing the unwanted stimulated Raman scattering and the resulting mode distortion while boosting the pulse energy with a shortest pulse width of sub-50 fs. Specifically, a maximum single pulse energy of 707 nJ and a peak power of 11 MW with a fundamental Gaussian distribution beam profile were respectively realized without temporally stretching the seed pulse. In addition, the backward pumped amplifier was further examined through changing its seeding power, and it is found that a relatively low input power is preferable for obtaining high performance laser pulses with shorter duration while without compromise on the output single pulse energy. It is believed that the combination of the GMN amplification and the large mode area tapered fiber provides a promising scheme for realizing high energy ultrafast lasers with a monolithic and concise structure.