A monolithic array of five noninteracting buried crescent lasers has been optically multiplexed using an external cavity with a grating as a dispersive element. The lasers have a center to center separation of 8 &mgr;m, and with an external cavity consisting of a 4‐mm focal length lens and a 600‐line/mm grating used in second order, the lasers emit at ≊1.31 &mgr;m in essentially single longitudinal modes separated by 19.6 A˚. Single longitudinal mode operation has also been obtained using a cleaved coupled cavity (C3) laser array. In this case the dominant mode is determined by the coherent interference of the mode spectrum of the two subcavities.