Facilitating Single-Transverse-Mode Lasing in VCSELs via Patterned Dielectric Anti-Phase Filters

A novel method to achieve single-fundamental-mode lasing and higher order mode suppression using a multi-layer, patterned, dielectric anti-phase filter is employed on the top of oxide-confined vertical-cavity surface-emitting lasers (VCSELs). Dielectric layers are deposited and patterned on individual VCSELs in a wafer-scale process to modify (increase/decrease) the mirror reflectivity across the oxide aperture via anti-phase reflections, creating spatially dependent threshold material gain and VCSEL lasing-mode control. A 1-D plane-wave propagation method is used to calculate the dielectric layer thicknesses in each spatial region needed to facilitate or suppress lasing. A single-fundamental-mode, continuous-wave output power of 3.5 mW is achieved at a lasing wavelength of 850 nm. This additive, non-destructive method allows for mode selection at any lasing wavelength and for any VCSEL layer structure without the need for destructive etching techniques or epitaxial regrowth. It also offers the capability of a tailored filter design based on available materials and deposition methods.