Abstract

It is now well known that the differential gain is enhanced in quantum well (QW) lasers by a factor of 4 compared with conventional double heterostructure (DH) lasers because of the steplike density of states. This enhancement is effective for the ultrashort pulse generation as well as increased modulation bandwidth.¹ In fact, an extremely short pulse as narrow as 1.3 ps is successfully achieved in the QW lasers.² On the other hand, to achieve efficient carrier injection, the quantum wells in the active layer should be appropriately coupled. However, this coupling reduces the quantum confinement effects, which results in suppressing the enhancement of the differential gain. We clarify the effects of the coupling between the wells on lasing dynamics in the gain switched QW lasers.

© 1990 Optical Society of America