Abstract: The multiple-active-region tunneling-regenerated strained-quantum-well vertical-cavity-surface emitting laser (VCSEL) with a more-than-one differential quantum efficiency is proposed.This multiple-active-region VCSEL is expected to have the improved performance of smaller threshold current and higher output power.Theorectically,the optimum DBR reflectivity with fixed supply current and series resistance as parameters is determined for this novel structure.Finally,the following conclusion is proved in theory:with the increase of active region numbers,this multiple-active-region structure can greatly enhance the output power and lower the threshold current density.