Characteristic Optimization of 1.3 μm High-Speed MQW InGaAsP-AlGaInAs Lasers

We investigate 1.3 μm multi quantum-well (MQW) lasers with InGaAsP (well) and InGaAlAs (barrier) on InP for high speed application, compared to the typical structures of InGaAsP (well)-InGaAsP (barrier)/InP and InGaAlAs (well)-InGaAlAs (barrier)/InP with the same quaternary in the well and barrier. We calculate the characteristics of band offset and gain of InGaAsP-AlGaInAs quantum wells (QWs). The advances of the new QW design are mainly rooted in the large ratio between conduction-band and valence-band offsets (ΔE_c:ΔE_v=7:1), higher than the typical value of 4:6 in InGaAsP-InGaAsP and 7:3 in InGaAlAs-InGaAlAs for 1.3 μm lasers. Due to the low confinement energy of holes, non-uniformity of carrier distribution over multi-InGaAsP-AlGaInAs QWs is significantly reduced. The enhancement of high-speed performance of InGaAsP-AlGaInAs MQW lasers is investigated in terms of turn-on oscillation.