Carrier confinement performance by multiple quantum barriers (MQB) is demonstrated in 1.55 &mgr;m strained GaInAs/AlGaInAs multiple quantum well (MQW) lasers grown by molecular beam epitaxy. The strained MQW lasers with MQB atp‐side optical confinement layer show larger characteristic temperature and slope efficiency at high temperature than those without MQB. It is also shown that the MQW lasers with MQB have less spontaneous emission from the optical confinement layer than the lasers without MQB. As another important result, it is demonstrated for the first time that the MQW lasers with MQB have less dependency of theKfactor on the temperature than the lasers without MQB. These results further verify the effective carrier confinement performance of GaInAs/AlInAs MQB structure. ©1995 American Institute of Physics.