A vertical cavity surface emitting laser (VCSEL) (100) has a substrate (104), on which are disposed first and second distributed Bragg reflectors (DBRs) (106, 112), each DBR comprising a stack of layers of alternating refractive index, an active layer (108) disposed between the DBRs, and an aperture layer (110) disposed either between the DBRs or within one of the DBRs. The aperture layer (110) has a border (116) having an internal boundary with a plurality of indented portions defining one or more apertures. Such a VCSEL is easily manufacturable and provides a narrow bandwidth output, as well as mitigating at least some of the problems of prior art VCSELs. Mesa (102) may be etched to be non-circular and subsequent selective oxidation of aperture layer (110) results in a non-circular current confinement aperture (114) promoting higher-order lateral modes (LP21).