Theoretical analysis of 980nm high power vertical external-cavity surface-emitting semiconductor laser (VECSEL)

Abstract

By using bottom-emitting structure, we will develop laser diode (LD) pumped 980 nm VECSEL with active region of InGaAs/GaAsP/AlGaAs system. Because the thickness of barrier layer and absorption layer exceed that of quantum well, single well approximation model (KP method) can be used to calculate the band structure of VECSEL. The Schrodinger equation of finite deep potential well can be adopted to calculate the energy level structures of electron, heavy and light holes. According to the transition selection rule, we theoretically obtained the emitting wavelength of VECSEL and calculated quasi-Femi energy of valence band and conduction band based on the analysis of energy level structure of electron and holes. By analyzing the gain of strained quantum wells, we calculated the gain of VECSEL using transition matrix elements of electron, heavy and light holes. We give out the threshold gain, output power and other characteristic parameters. We will study the configuration of VECSEL and pumping scheme. We designed external cavity mirror, active region and bottom-emitting structure. A LD-pumped vertical external cavity surface-emitting laser whose output power is greater than 1.0 W can be predicted.