Optical gains of type-Ⅱ InGaAs/GaAsBi quantum wells (QWs) with W,N,and M shapes are analyzed theoretically for near-infrared laser applications.The bandgap and wave functions are calculated using the self-consistent k · p Hamiltonian,taking into account valence band mixing and the strain effect.Our calculations show that the M-shaped type-Ⅱ QWs are a promising structure for making 1.3μm lasers at room temperature because they can easily be used to obtain 1.3 μm for photoluminescence with a proper thickness and have large wave-function overlap for high optical gain.