Q-switched mode-locking and continuous-wave mode-locking operation in a short-cavity erbium-doped fiber laser

We demonstrate a short-cavity Q-switched mode-locking (QML) and continuous-wave mode-locking (CWML) erbium-doped fiber (EDF) laser based on graphene-oxide (GO) as a passive ssaturable absorber (SA). By film-drying and inserting GO between two fiber connectors, passive GO SA is constructed. The GO SA is then incorporated into a short EDF laser cavity. The laser can operate both on QML pattern and CWML pattern just by adjusting the pump power. The mode-locking pulse duration can be as short as ∼472 fs. And the fundamental repetition frequency can be 111.4 MHz.