Locking range analysis of two diode-pumped solid state lasers coherently coupled by an internal Fourier filter

An analytical expression for the locking range of two lasers was derived by a theoretical model describing the coherent coupling in a common cavity by means of an internal lens and a Fourier-filter. The theoretical predictions were experimentally proved using two diode- pumped solid-state lasers by thermally detuning one laser and analyzing the far field pattern in the locked and the unlocked state.