Abstract
A coupled-cavity vertical-emitting semiconductor laser is built. It intrinsically allows the beating of two longitudinal modes owing to a weak coupling between the matched optical cavities. Terahertz electromagnetic waves have to be produced by external photomixing. First, analytical analysis enables design rules to be applied for such a purpose. Secondly, the fabrication and characterisation of a coupled-cavity VCSEL operating at 980 nm is described. The fabricated device shows a low laser threshold and exhibits the coupling between both cavities, although continuous-wave terahertz two-mode beating has not yet been observed