Architecture laser resonator

A resonator (5) laser comprising: a coupler (10a) output; a reflector (10b) end; a retroreflector (15); a telescope (20); means (25) gain; characterized in that the telescope (20) is a common telescope, in which the common telescope is shared by at least two arms or paths (50a, 50b) of the resonator telescope common telescope provided in beam paths (50a, being 50b ) between the retroreflector (15) and both the reflector (10b) as the coupler end (10a) output.