Virtual mesa and spoiler midinfrared angled-grating distributed feedback lasers fabricated by ion bombardment

It is demonstrated that the suppression of parasitic Fabry-Perot-like lasin g modes substantially enhances the beam quality and brightness of wide-stri pe angled-grating distributed feedback lasers emitting in the midwave infra red. The direct facet-to-facet gain path is blocked by loss regions that ar e created by ion bombardment with 900 keV silicon ions. Both virtual mesa s tructures, in which loss regions bound both sides of the 300-mum-wide angle d gain path, and spoiler structures, in which loss is induced only near the facets, decrease the etendue of the output by nearly an order of magnitude , and increase the brightness by up to a factor of 3. (C) 2001 American Ins titute of Physics.