Self-induced modulational-instability laser.

We analyze the transition from passive mode locking into the novel modulational-instability regime of erbiumdoped fiber lasers. By including in the cavity an anisotropic loss, we observed, depending on the polarization setting, the generation of either single pulses as short as 435 fs or a continuous-wave train of 3.5-ps-long solitons at a repetition rate of 76 GHz. Even with no anisotropic losses in the cavity, soliton trains at a repetition rate of as high as 130 GHz were still observed. We believe that this is the first observation of a self-induced modulational-instability laser.