Application of organometallic vapor phase epitaxy on patterned substrates for a new monolithic laser waveguide butt coupling technique

An important issue in the realization of monolithic optical circuits is the coupling of laser to optical waveguides. To obtain these structures, we have studied the epitaxial growth of GaAs/GaAlAs superlattices by organometallic vapor phase epitaxy on patterned substrates, with mesa along the [011] and the [011̄] directions. By careful adjustments of the mesa profile and on the layer thicknesses, we have grown in a single step structures containing a waveguide and a laser in such a way that the active layer and the transparent optical waveguides are directly butt jointed. Broad-area lasers exhibit typical threshold current of 1.5 kA/cm2. Coupling efficiency up to 70% has been measured on some devices.