Fig. 1. Simulation results. (a) Material gain spectra of different barrier materials corresponding to the active region at a carrier concentration of 5×10¹⁸ cm^-3 at 300 K using InGaAs as a quantum well; (b) simulated material gain spectra of the active region of InGaAs/AlGaAs at a carrier concentration of 5×10¹⁸ cm^-3 at temperatures from 300 K to 400 K

Fig. 2. Simulation results. (a) Round-trip phase at different temperatures; (b) relationship between peak gain wavelength and resonant wavelength and active region temperature at different temperatures

Fig. 3. Structure diagram of top-emitting 940 nm VCSEL

Fig. 4. Fabrication process flow chart of top-emitting 940 nm VCSEL

Fig. 5. SEM images of top-emitting 940 nm VCSEL. (a) Device surface view; (b) device cross-sectional view;（c）infrared microscopy images of VCSELs with different oxide apertures

Fig. 6. 940 nm VCSEL with oxide-defined apertures of 2-7 μm at room temperature. (a) P-I-V test curves; (b) PCE test curves

Fig. 7. Spectra of 940 nm VCSELs with different oxide-defined apertures driven by 3 mA continuous current at room temperature

Fig. 8. 940 nm VCSELs with an oxide-defined aperture of 2 μm. (a) Spectra at different injection currents; (b) center wavelength and SMSR at different drive currents

Fig. 9. Far-field divergence angle test curves under different drive currents of 940 nm VCSEL with an oxide-defined aperture of 2 μm

Fig. 10. 940 nm VCSEL with an oxide-defined aperture of 2 μm. (a) Spectral test plots at 2 mA continuous drive current for temperatures from 10 °C to 80 ℃; (b) spectral test plots at 5 mA continuous drive current for heat sink temperatures from 10 ℃ to 80 ℃; (c) excitation center wavelength and SMSR of the device at different heat sink temperatures under 2 mA and 5 mA continuous drive currents; (d) P-I output curves of heat sink temperature from 10 ℃ to 80 ℃