The study of 80 MHz Self starting passively mode-locked Erbium-Doped Fiber Laser via nonlinear polarization rotation with SESAM

Erbium-Doped Fiber Laser, EDFL, passively mode-locked via onlyNonlinear Polarization Rotation, NPR, and via NPR with SemiconductorSaturable Absorber Mirror, SESAM, is studied. Self start single pulse trainwith pulse width of 114 fs and repetition rate (PRR) of 80 MHz has beenobtained when 55 cm EDFL, passively mode-locked via NPR only. InsertingSESAM in EDFL cavity leads to shorten the pulse width up to 88 fs, increasesthe amplitude stability up to 96% and lower the phase noise jittering to around26 fsec. Stable second harmonic self starting passively mode-locked EDFL withpulse width of 284 fs has also been observed only when SESAM was used in thecavity. Multi-pulsed system passively mode-locked via NPR for EDFL length of80 cm with time difference between the successive multi-pulses ranged fromfew picoseconds to nanoseconds, has been observed. The time difference can becontrolled by the polarizer controller and the half wave plate. Furthercontrolling of the cavity polarization leads to developing the multiple modelockingpulses train to second harmonic mode-locking pulse train with PRR of160MHz and pulse width of 156 fs. Three harmonic superposed trains of modelockedpulse have been achieved only when SESAM added to the cavity