61-GHz dark-soliton generation and propagation by a fiber Bragg grating pulse-shaping technique

We report the experimental shaping of dark-soliton pulse trains at a several-gigahertz repetition rate by means of a simple sinusoidal fiber Bragg grating used as a highly resolving passive filtering element at the output of a conventional mode-locked laser source. We show that the proper choice of grating parameters allows for the transformation of bright-pulse trains into odd-symmetry dark-pulse trains with cw background. The results of a propagation experiment with a 7-km-long fiber demonstrate, together with numerical simulations, the efficiency of the new shaping method.