Ultimate limit in low threshold quantum well GaAlAs semiconductor lasers

Abstract

Gain measurements were performed on buried heterostructure single quantum well lasers to ascertain the transparency current density, which represents a basic limit in the threshold current. By using the optimal design approach, a lowest threshold of 0.55 mA in a 120-μm-long device was achieved. Modulation of the low threshold laser by a pseudorandom digital stream at 1.3 Gbit/s without current bias is demonstrated.