Theoretical study of differential gain in strained quantum well structures

The differential gain expected in a strained quantum well (QW) and in a lattice-matched QW is discussed based on a theoretical treatment of the band structures where the band nonparabolicity is taken into account. The differential gain in strained QWs will be larger by about three to four times relative to lattice-matched QWs, and a maximum differential gain of 4-6*10/sup -15/ cm/sup 2/ will be possible in strained QWs. The anisotropy of the subband nonparabolicity in lattice-matched QWs contributes to the larger difference between the two types of QWs. The calculated band-edge effective masses and the calculated laser properties, are compared to the available measurements, and some comments are given for realizing high-speed strained lasers.>