Study And Design Of High-Performance 760 Nm Vertical-Cavity Surface-Emitting Laser

In recent years,the tunable diode laser absorption spectroscopy has been widely used in gas sensing,remote detection of toxic gas leaks,atmospheric quality monitoring and other fields.It is essential to monitor oxygen concentrations in enclosed environments,industrial and medical scenarios.In this application,high-power output is necessary to meet the demands of longer detection distances and improved detection capabilities.Therefore,research in this area is highly urgent.Based on this application,this thesis focuses on the study and design of high-power 760 nm vertical-cavity surface-emitting lasers from two aspects:strained quantum well design and two-junction vertical cavity surface emitting lasers.The main research contents are as follows:1.Mainly studied the influence of tensile strain and compressive strain on the material energy band and different mechanisms for improving the performance of lasers.The material gain as a function of strain variation is calculated and then designed the quaternary compound compressive strain quantum well(In_0.15Ga_0.65Al_0.20As)and tensile strain quantum well(In_0.15Ga_0.85As_0.62P_0.38).Combined with the valence band subband splitting diagram and Auger recombination rate,it is demonstrated that compressive strain can reduce the hole effective mass,decrease the density of states at the valence band maximum,enable a lower injection carrier level to reach the threshold,and consequently reduce the Auger recombination rate.This results in a decrease in VCSEL threshold current from 1.8 m A to 1.04 m A.Additionally,the variation in p-state polarization distribution indicates an enhancement in gain,leading to an increase in output power.2.Thesis further designed a double-junction vertical-cavity surface-emitting laser.In this section,including the effect of material selection,doping concentration and tunnel junction’s thickness on the tunneling probability have been studied.Finally designed a tunnel junction with low absorption loss and high tunneling probability,and inserted an electron/hole blocking layer in the double junction structure.The results show that the slope efficiency is doubled from 0.94 W/A to 1.94 W/A compared with the single-junction device,and the maximum output power increased from 22.02 m W to 30.91 m W due to the principle of carrier regeneration in tunneling process,and the power-to-light conversion efficiency also increased.Moreover,the thermal performance of the double-junction device also gets improved.