EFFECTS OF STRAIN IN MULTIPLE QUANTUM-WELL DISTRIBUTED FEEDBACK LASERS

A survey of graded-index separate confinement multiple quantum well distributed feedback lasers comparing the effects of strain in the quantum well upon threshold, output power, and linewidth is reported. Lasers with either compressive or tensile strained quantum wells and a long cavity length (890 μm) show lower threshold current (10-20 mA) as well as lower linewdith power product than lasers with unstrained quantum wells and have a comparable minimum linewidth to the unstrained quantum well lasers. A minimum linewidth as narrow as 900 and 440 kHz for compressive strain and unstrained quantum well lasers, respectively, was obtained at output power of 30 mW. Single longitudinal mode operation with a maximum output power over 80 mW was observed in all the structures.