Abstract: Diode lasers comprise a substrate and a number of material layers disposed thereon that include a P-type material layer, and an N-type material layer. A gain layer and diffraction grating feedback layer can be also be included in the material layers. The material layers are formed by epitaxial deposition, during which process a wall surface common to the material layers is also formed. This wall surface forms an internally reflective wall surface within the material layers that is oriented to reflect a laser beam internally within the diode laser construction towards a top or bottom surface of the diode laser for emission therefrom. In an preferred embodiment, the internally reflective wall surface is oriented at a 45 degree angle, and the laser beam is reflected by the wall surface to emit the laser beam from the diode laser at a 90 degree angle relative to the top or bottom surface.