Coherent operation of a monolithic linear array of InGaAsP buried‐heterostructure lasers operating at &lgr;=1.3 &mgr;m has been acheived by means of a spatial filter in an external cavity. An array of mass‐transported InP microlenses was used to collimate the beams of the individual laser elements and couple the laser array output to the external cavity. The coherent array output exhibited a narrow (3.2 mrad), three‐lobe far‐field pattern with ∼65% of the energy concentrated in the central peak.