Antireflection-coated angled facet design

New and accurate semianalytical expressions, based on the free-space radiation mode method, are derived for the reflectivity of a polarised guided mode of a slab waveguide incident on a multicoated laser facet at an arbitrary angle. Solutions may be obtained simply and with minimum computational effort. Results presented confirm that the coated angled facet can reduce the guided-mode reflectivity to near zero for both polarisations. The far-field radiation pattern is also significantly modified by angling the waveguide to the facet