Erbium-Doped Fiber Laser, EDFL, passively mode-locked via only
Nonlinear Polarization Rotation, NPR, and via NPR with Semiconductor
Saturable Absorber Mirror, SESAM, is studied. Self start single pulse train
with pulse width of 114 fs and repetiti
on rate (PRR) of 80 MHz has been
obtained when 55 cm EDFL, passively mode-locked via NPR only. Inserting
SESAM in EDFL cavity leads to shorten the pulse width up to 88 fs, increases
the amplitude stability up to 96% and lower the phase noise jittering to around
26 fsec. Stable second harmonic self starting passively mode-locked EDFL with
pulse width of 284 fs has also been observed only when SESAM was used in the
cavity. Multi-pulsed system passively mode-locked via NPR for EDFL length of
80 cm with time difference between the successive multi-pulses ranged from
few picoseconds to nanoseconds, has been observed.