Phase-locking principle of axisymmetric structural CO_2 laser and theoretical study of the influences of parameters-changes on phase-locking

Based on the injection-locking principle, the phase-locking mechanisms of axisymmetricfold combination CO2 lasers are analyzed. Then influences of parameters-changes on phase-locking are studied in detail, such as changes of cavity length and curvature radius, linewidth, phase error, and coherence time. It is shown that these factors almost do not influence the degree of mode coupling, but they could influence distribution of light intensity to some degree. Phase-locking can improve the value of maximum light intensity significantly; what is more, the numerical calculation indicates that the higher the fringe visibility the better the coherence.