Hybrid mode-locking based on nonlinear polarization rotation in a SOA fiber ring laser

A hybrid actively and passively mode-locking semiconductor optical amplifier fiber ring laser based on nonlinear polarization rotation was presented, where intensity modulator not only acted as modulator but also polarizer. Under the hybrid mode-locking mechanism, output pulse is with some new characters. So, a theoretical model that describes the SOA fiber ring laser was developed and system parameters effects on mode-locking pulse are discussed.