Stabilizing the soliton laser

In the soliton laser, feedback from a pulse-shaping fiber enables the production of ultrafast pulses of controlled shape and width. Successful operation, however, requires maintenance of the correct optical phase of this feedback. A simple but effective servo control that locks to the required phase while simultaneously stabilizing output power is described. It is shown that the stabilized soliton laser action involves passive mode-locking. Finally, experiments that reveal, in considerable detail, how the pulse shaping takes place are described. In particular, the experiments show that closure is not required separately of the laser's two coupled cavities.