title: Flattop mode shaping of a vertical cavity surface emitting laser using an external-cavity aspheric mirror.
abstract: Both square-shaped and circular-shaped flattop modes were experimentally demonstrated in extended-cavity broad-area VCSELs using aspheric feedback mirrors. These refractive aspheric mirrors were fabricated by electron-beam lithography on curved substrates. Excellent single-mode operation and improved power extraction efficiency were observed. The three-mirror structure of the VCSEL and the state-of-the-art fabrication of the aspheric mirror contribute to the superior VCSEL performance. The modal loss analysis using a rigid three-mirror-cavity simulation method is discussed.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Yang
authors.forename: James
authors.initials: J
authors.lastname: Leger