Direct control of mode-locking states of a fiber laser

Mode locking is a non-equilibrium steady state. Capability to control mode-locking states can be used to improve performance as well as shed light on non-equilibrium physics using the laser as an experimental platform. We demonstrate direct control of the mode-locking state using spectral pulse shaping by incorporating a spatial light modulator at a Fourier plane inside the cavity of an Yb-doped fiber laser. We show that we can halt and restart mode locking, suppress instabilities, induce controlled reversible and irreversible transitions between mode-locking states, and perform advanced pulse shaping while using pulses as short as 40 fs.