Phase locking of eight wide-aperture semiconductor laser diodes in one-dimensional and two-dimensional configurations in an external Talbot cavity

Phase locking of the output radiation and mode selection were achieved experimentally in an external Talbot cavity, of length L = Z(T)/4 and containing one linear array of eight wide-aperture laser diodes each 120 mu m wide. Such phase locking was also attained for two parallel linear arrays. The radiation from a single linear array was characterised by the contrast parameter V = 0.97 and by the angular width of the diffraction maxima amounting to 0.5 mrad at half-intensity, corresponding to the diffraction limit for a linear array with a diode spacing period d = 200 mu m. A cavity with a tilted mirror was investigated and the feasibility of increasing the radiation intensity in the central lobes was demonstrated. Phase locking was attained experimentally for two linear arrays separated by a distance of 1600 mu m. The angular width of the maxima was 0.5 mrad in the p-n junction plane and 0.25 mrad in a plane perpendicular to the junction.