(AL,GA)As Double-Heterostructure Lasers: Comparison of Devices Fabricated with Deep and Shallow Proton Bombardment

An important goal of recent injection-laser applied research has been the development of a laser structure that combines the desirable features of good optical linearity, absence of temporal instabilities, high reliability, and a high-yield, simple fabrication process.1 With regard to optical linearity, it has been known for some years that controlling the lateral mode motion in stripe-geometry lasers by narrowing the stripe width results in greatly improved linearity of light versus device current (above threshold).2 However, in proton-bombardment-delineated structures in which the proton damage penetrates the active region of the laser, it has been difficult to narrow the stripe width below about 8 jum without encountering serious increases in lasing current threshold due to excess carrier losses at the stripe edges. This has resulted in the consideration of devices in which the 975 Fig. 1--Light vs current for lasers of varying stripe width (w = 12, 8, 5 /xm) and shallow proton damage (100 keV).