An integrated buried heterojunction laser optically coupled to a ridge waveguide electro-absorption (EA) optical modulator having a raised ridge structure is manufactured on a single semiconductor substrate on which a plurality of semiconductor layers are grown, including at least one active layer through which optical radiation is coupled from the laser to the waveguide. Semiconductor layers above the active layer form a laser current conduction region and semiconductor layers adjacent the active layer form a laser current confinement region. The ridge structure is formed from one or more layers also used to form the laser current conduction region. The layers used to form the laser current confinement region do not extend adjacent the ridge structure.