  Self-induced transparency mode-locking (or coherent mode-locking, CML) which
is based on intracavity self-induced transparency soliton dynamics, allows
potentially to achieve nearly single cycle intracavity pulse durations, much
below the phase relaxation time $T_2$ in a laser, which, despite of great
promise, has not yet been realized experimentally. We develop a diagram
technique which allows to predict the main features of CML regimes in a generic
two-section laser. We show that CML can arise directly at the first laser
threshold if the phase relaxation time is large enough. Furthermore, CML
regimes can be unconditionally stable. We also predict the existence of
``super-CML regimes``, with a pulse coupled to several Rabi oscillations in the
nonlinear medium.
