Output power of dynamic distributed feedback dye lasers

An experimental investigation was made of the output power of a volume dynamic distributed feedback (DDFB) laser as a function of the pump power and optical density of the active medium in order to determine the conditions for maximum energy efficiency. It was found that at certain high pump powers, the degree of coupling between the forward and backward stimulated emission waves in a DDFB laser increases so substantially that a considerable proportion of the output power is scattered inside the structure. This effect is observed as a "saturation" region in the dependence of the output power on the pump power. It is shown that saturation can be avoided, at least in this pump power range, by decreasing the coupling between the forward and backward waves. A qualitative comparison is made with the theory.