Thermal index guiding in (AlGa)As proton-isolated lasers: its origins and reduction by post-implantation heat treatment

Free-carrier-induced index-antiguiding and thermal index-guiding effects in the proton-isolated, (AlGa)As separate confinement heterostructure laser diodes have been investigated in the pulse and CW conditions. The thermal index guiding-induced far field narrowing has been used to evaluate the temperature rise in the active region during the laser pulse. The observed coincidence of strong thermal index-guiding with high series resistance and other unwanted properties of devices (which depend on H⁺-implantation parameters) indicated on a presence of defects in the stripe region. It has been found that proper post-implantation heat treatment of the heterostructure slice can reduce thermal effects and improve laser characteristics. A proposed explanation is the heating-out of the implantation-induced defects in the stripe region