Narrow stripe graded barrier single quantum well lasers-threshold current considerations

It is observed that narrow stripe graded barrier single quantum well lasers are relatively high threshold current devices ( > 50 mA), even though made from wafers with extremely low broad area threshold current density (<300 A/cm
²
). Besides, they show a complex time-dependent lasing behavior with sequential lasing from the
n = 2
and
n = 1
quantum levels. It is shown here that these properties are inherent to narrow stripe gain-guided SQW lasers and are dictated by the nature of the optical gain curve of the quantum well.