Low threshold, high quantum efficiency, high speed strain compensated multiquantum well lasers

Fabrication and characteristics of quaternary/quaternary multi quantum well lasers with and without strain compensation emitting at 1.55 μm are reported. A zero-net strain structure was achieved by growing InGaAsP wells with compressive strain and InGaAsP barriers with tensile strain, and compositions chosen such that the As/P ratio was the same in the wells and in the barriers. Fabry-Perot and DFB laser diodes were fabricated and characterised. Measured threshold currents as low as 4.3 mA and quantum efficiencies higher than 30% per facet were obtained for devices with as-cleaved mirrors