A novel SBS-laser oscillator scheme with active and passive mode locking

Schemes to achieve mode locking and synchronization in a phase conjugating stimulated Brillouin scattering (SBS)-oscillator are presented. The first scheme involves a SBS-laser oscillator with active support of mode synchronization by an acousto-optic modulator. The second scheme involves passive mode synchronization by feedback mirror. Average output powers up to 7 W could be realized in a mode locked passively Q-switched regime. The dynamics of the longitudinal modes is discussed on the bases of two different numerical models, a rate equation based multi mode model and a round trip based model. Both schemes are realised with a Nd:YAG rod as laser active material.