Volet, NicolasCzyszanowski, TomaszWalczak, JaroslawMutter, LukasDwir, BenjaminMicković, ZlatkoGallo, PascalCaliman, AndreiSirbu, AlexeiMereuta, AlexandruIakovlev, VladimirKapon, Eli2013-11-202013-11-202013-11-20201310.1364/OE.21.026983https://infoscience.epfl.ch/handle/20.500.14299/97112WOS:000327007800156Transverse mode discrimination is demonstrated in long-wavelength wafer-fused vertical-cavity surface-emitting lasers using ring-shaped air gap patterns at the fused interface between the cavity and the top distributed Bragg reflector. A significant number of devices with varying pattern dimensions was investigated by on-wafer mapping, allowing in particular the identification of a design that reproducibly increases the maximal single-mode emitted power by about 30 %. Numerical simulations support these observations and allow specifying optimized ring dimensions for which higher-order transverse modes are localized out of the optical aperture. These simulations predict further enhancement of the single-mode properties of the devices with negligible penalty on threshold current and emitted power.text::journal::journal article::research article