Dislocations are used as “atomic saws’’ to cut a 5 nm GaAs quantum well into a multiple quantum wire structure. The direct observation of these cuts in the volume, was performed by transmission electron microscopy, using cross section specimens, thinned perpendicular to the quantum wire axis by a highly localized preparation technique. This special thinning procedure, involving electron-beam lithography and reactive ion etching, allowed us to realize a statistical analysis of the distances between neighboring cuts and the heights of cuts. This dimensional analysis revealed the formation of coupled quantum wires with a width of 18±9 nm and free from any lateral roughness on 100 nm lengths. ©1997 American Institute of Physics.