Modeling harmonically modelocked fiber lasers

Summary form only given. Modelocked erbium-doped fiber lasers which are used for communication should work with high repetition rate. The length of fiber lasers is usually long and therefore such lasers must be harmonically modelocked, One of the main problems in such mode of operation is pulse dropout. However, theoretical models often assume that a single pulse propagates inside the laser so that analysis of the pulse dropout is not possible. Several methods for overcoming pulse dropout have been demonstrated experimentally; however, stable operation could only be obtained over a limited range of pulse durations and the limits have been poorly understood. In this work we describe an innovative numerical approach that allows us to successfully model laser systems which are based on slow saturable gain. We also present a reduced model that yields insight into the behavior.