Spatial hole burning problems in evanescently coupled semiconductor laser arrays

Abstract

The effect of spatial hole burning on laser arrays is theoretically analyzed. Due to the nonuniformity of the lowest order supermode, carriers are unevenly depleted when this mode is excited. This spatial hole burning in carrier concentration reduces any designed discrimination against higher order supermodes. More and more modes are excited as the power level goes up, resulting in broadened radiation patterns. Even when the lowest order mode oscillation can be guaranteed, spatial hole burning modifies the refractive index profile. The intensity distribution of this mode narrows as power increases. The results are broadened radiation patterns and low quantum efficiency. Two methods to overcome these problems are briefly discussed.