Effects of the Current Distribution on the Characteristics of the Semiconductor Laser with a Channeled-Substrate Planar Structure

摘要

Effects of the current distribution along the junction plane on the lateral and longitudinal mode behaviors of the semiconductor laser with a channeled-substrate planar (CSP) structure are investigated experimentally and theoretically. A new laser structure of the double-current-confinement CSP type, which has two electrodes for pumping and only one channel for stimulated emission (TEPOSE), was employed for this study. Current distribution profile of this laser can be varied by changing the relative strength of the current in each electrode. Experimental results showed that an asymmetric current profile can degrade the fundamental-lateral mode operation. A theoretical model based on phase-locked two-mode excitation was deveoped to account for the far-field pattern of a TEPOSE laser with only one electrode excited. It is also found that nonuniform excitation over the lasing mode can lead to multi-longitudinal mode, probably due to nonuniformity in the quasi-Fermi level separation. The present study demonstrates the importance of symmetric and uniform current distribution in designing semiconductor lasers. (Author)