A technique for achieving stable preparation of anisotropic oxide aperture VCSELs

High-temperature operating characteristics and polarization stability are important for VCSEL as an atomic clock light source. In this study, the polarization-stable single-mode 795 nm VCSEL with anisotropic aperture was successful fabricated by controlled the asymmetric airflow distribution and the different oxidation rates of the crystal direction. The oxidation of different crystal direction of asymmetric oxidation aperture with time is summarized. The surface electric fields of the traditional circular oxidation aperture VCSEL(C-VCSEL) and diamond shape oxidation aperture VCSEL(D-VCSEL) with different aperture sizes are investigated by simulation, and then the cause of the anisotropy of D-VCSEL is explored. The special anisotropic oxidation aperture of the device makes it have stable polarized characteristics. The demonstrated D-VCSEL with dimensions of 3.6 μm × 4.8 μm, achieving an orthogonal polarization suppression ratio (OPSR) exceeding 30 dB while maintaining low threshold and high single-mode output even at temperatures up to 80 °C.