Performance characteristics of strained InGaAs/AlGaAs quantum well lasers

Strained InGaAs quantum well (QW) lasers have been used to extend the lasing wavelength of quantum well lasers form --0.9 out to nearly 1.1 μm. The structures reported here are grown by atmospheric pressure organometallic vapor phase epitaxy (OMVPE). As shown by the composition profile, they are functionally equivalent to low threshold GaAs/AlGaAs QW lasers, except for a strained InchiGa1-chiAs QW active region replacing the normally unstrained GaAS QW active region. Due to the effects of biaxial compression on the InGaAs QW, such structures have been predicted to have lower threshold currents than similar unstrained structures. Here in InchiGa1-chiAs QW compositions 0.2 < chi < 0.3 and QW thickness 70 A < h < 125 A are investigated. In devices where the accumulated strain energy is relatively low (that is, low InchiGa1-chiAs alloy composition (chi=0.2) in a narrow (h=70 A) QW), performance is comparable with GaAs QW lasers grown in the same OMVPE reactor