Stable VCSEL mode discrimination realized by a ring-shaped dielectric relief

Abstract

We demonstrated a method of transverse mode selection of vertical-cavity surface-emitting lasers (VCSELs). A ring-shaped anti-phase SiO2 layer was introduced to filter the modes whose intensity distribution overlapped with the extra layer. The effective index method considering the size of the oxide aperture was applied to decide the inner/outer radius of the ring. Conventional reference device and two-round of confirmatory studies of ring-shaped SiO2 VCSEL were fabricated and characterized. In comparison with the spectra of the conventional VCSEL, the VCSELs with ring-shaped SiO2 layer emitted two stable transverse modes over the entire current range. This method may offer a new idea to solve the device request for the few-mode optical communications in the future.