| 摘要 |
An optical waveguide structure according to the invention comprises a core layer having a first refractive index ncore, an array of sub-regions within the core having a second refractive index nrods, the array of sub-regions giving rise to a photonic band structure within the core layer, and a cladding layer adjacent to the core layer having a refractive index ncladding, wherein: ncore>nrods>=ncladding and ncore-nrods>0.1. The structure of the present invention is less lossy than prior waveguide structures having photonic bandstructure regions. The out of plane divergence of light in the sub-regions is reduced as compared with air holes which are typically used in photonic crystal structures. As a result more light is coupled back into the core at the sub-region/core interface. Coupling of light into the buffer layer is also reduced. Furthermore, there are added advantages over the prior art associated with the fabrication of these structures.
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