Lateral current spreading in stripe laser diodes

Lateral current spreading is experimentally and theoretically investigated in stripe laser diodes. The influence of current spreading length to threshold current density is quantitatively analyzed. The factors of current spreading length that residual thickness, resistivity of upper cladding layer, injected current density are numerically calculated. It is found that effective current rate declines with the injected current increasing and resistivity affects the current spreading length dramatically. A critical injected current density exists below which the slope efficiency increases with the injected current density increasing. Above this critical value, the slope efficiency declines with the injected current density increasing. This critical value helps to find the best work current, which can extend the lasers' life.