Table 1.

Standard (incoherent) passive mode-locking (PML) and coherent mode-locking (CML).

Standard passive mode-locking (PML)	Coherent mode-locking (CML)
Based on incoherent (${\tau }_p>T_2$) gain/absorption saturation	Based on Rabi oscillations
${\mathrm{\Omega }}_R<1/T_2$, $T_2<{\tau }_p<T_1$	${\mathrm{\Omega }}_R>1/T_2$, ${\tau }_p<T_2<T_1$
Significant part of energy is left in absorber	Almost no losses in absorber ($2\pi$-pulse of SIT)
Only part of energy is taken from the amplifier	Almost all energy stored in the amplifier is taken ($\pi$ pulse)
${\tau }_p$ is fundamentally limited by $T_2$	${\tau }_p$ can be much smaller than $T_2$
Few-cycle pulses are possible only in a broadband media	Few-cycle pulsese are possible in narrowband media
${\tau }_p$ typically increases with increase of the pump power	${\tau }_p$ decreases with the pump power