We realized self-mode-locking in a three-mirror-cavity Ti:sapphire laser wi
th a low pump power. The variation of the mode-locked region with cavity pa
rameters was studied experimentally, the astigmatism, stability, beam param
eters and self-focusing strengths of the laser cavity were calculated. The
results provide a theoretical basis for the design and align ment of this k
ind of laser cavities.