Coherent addition of adjacent lasers by forked eigenstate operation

Forked laser eigenstates are shown to provide a powerful tool both to phase lock spatially separated laser oscillators and to add their powers coherently into a TEM00 output beam. Coherent addition of the powers extracted from two fiber-coupled diode-pumped Nd:YAC channels is theoretically and experimentally demonstrated. Pure TEM00 oscillation is obtained with a 20% optical-to-optical conversion efficiency. The coherence of the two-propagation-axis laser is proved, and single-frequency operation is demonstrated. The scalability of the scheme is discussed. (C) 1998 Optical Society of America.