Pulse-Width Tuning in a Passively Mode-Locked Fiber Laser With Graphene Saturable Absorber

An absorption-adjustable graphene saturable absorber is used in a simple fiber laser system for an active control of the pulse-width of optical pulses. Such a saturable absorber is created by tightly attaching the graphene film onto the upper surface of the microfiber, thus an enhanced evanescence-field interaction between the propagating light along the microfiber length and graphene can be achieved. By tuning the polarization state of the light beam launched into the saturable absorber from TE to TM mode, the pulse-width of the pulses is varied between ~ 9.24 and ~ 2.32 ps.