Vertical Cavity Surface Emitting Laser (VCSELs) as the ideal light source for rubidium (Rb) and cesium (Cs) atomic clocks is analyzed for its mode and polarization control. We fabricated three kinds of shapes: triangular, elliptic and circular oxidation aperture which also has different sizes. We formed 3 different shape oxide apertures by wet-oxidation with 36-39μm circular mesa. Our results show that triangular oxidized-VCSELs has the advantages of mode and polarization selection over elliptic and circular oxide aperture. When triangular oxide-confined VCSELs emit in single mode, the measured Side Mode Suppression Ratio (SMSR) is larger than 20 dB and Orthogonal Polarization Suppression Ratio achieves 10 dB. Resonant blueshift of VCSELs with triangular and elliptic aperture is observed with the decrease of aperture size.

We designed and demonstrated a temperature-stable, wide-tuned, high-power Vertical External Cavity Surfaceemitting Laser (VECSEL) with a simple linear cavity. The quantum well is optimized by using the commercial PICS3D software to obtain wide gain and good thermal performance. The curve of BF has also been optimized, and a birefringent filter (BF) with a thickness of 1mm is selected as the tuning element. Then, we obtained a continuously adjustable range cover from 1044.5 nm to 1092.1 nm, 8 W of output power, and temperature-stable VECSEL, which verifies the feasibility of the design. Based on the experimental results, we concluded that the gain intensity corresponding to the tuning range should be at least greater than 163 e 26 /cm -3 s -1 eV -1 before the growth process ensures a wide tuning range. For the first time, to the best of our knowledge, we designed and obtained the tuning result of VECSEL in the linear cavity, and this is of great significance to the design of VECSEL with wide-tuning, high-power, and good temperature stability.