Stability of three-mode emission of a broad-band laser with an extended active medium

A theoretical analysis is made of the generation of three frequency-equidistant modes locked to a homogeneous gain line of width of the order of the width of a luminescence band of a dye solution. A relationship is established between stable intermode frequency intervals and the dynamics of lasing, on the one hand, and the length of the active medium and its position in a cavity, on the other. The characteristics of three-mode lasing are compared with two-mode characteristics in the same frequency interval.