Experimental and theoretical studies on colliding pulse mode locking

Experimental and theoretical studies on colliding-pulse mode locking (CPM) are presented. The equations of the theoretical model take into account all the orders in pulse energies and the results are calculated numerically. It is shown that the CPM laser has an asymmetric pulse shape which can be approximately expressed in terms of the "asymmetric hyperbolic secant" function,
[\exp (-t/T_{1}) + \exp (t/T_{2})]^{-2} (T_{1} < T_{2})
. The experimental results on the pulse shape and pulse width of the CPM ring dye laser are compared to the numerical ones.