Multiple stripe leaky mode laser

Claim 1

A semiconductor laser comprising: a substrate of semiconducting material; a plurality of stripe regions on the substrate, each having an active layer in which lasing is induceable by injection of charge carriers; each of the stripe regions including: (a) a first clad layer of semiconducting material positioned on the substrate and having lower refractive index than the active layer, the active layer being positioned on the first clad layer; (b) a second clad layer of semiconducting material positioned on the active layer and having lower refractive index than the active layer; a plurality of passive regions of semiconducting material positioned on the substrate, adjacent stripe regions being laterally separated by one of the passive regions, the passive regions and the stripe regions being configured to provide leaky mode optical coupling between adjacent stripe regions; each passive region having a refractive index higher than the effective refractive indices of adjoining stripe regions, at least one of the stripe regions including a zone at a lateral boundary having refractive index higher than the effective refractive index of the stripe region but lower than the refractive index of the passive region adjoining the boundary; a pair of mirrored facets at opposite ends of the substrate; and electrode means for supplying electrical current.