摘要 |
A waveguide component has a slab waveguide, a rib waveguide, and a mode transition section where the rib waveguide and the slab waveguide are adjacent, and where the rib waveguide is tapered, to provide optical coupling, and lateral confinement rib waveguides are provided along the slab waveguide in the mode transition section to confine light from spreading laterally. The lateral confinement ribs can be formed in the same step with the same mask as used for the taper, to ensure alignment with the taper. They can be arranged either side of the taper. The lateral confinement ribs are significant for enabling a mode transition section which couples with low loss. In particular, it reduces the need for the taper to be so fine, or the taper to be made in both vertical and horizontal axes, both of which cause fabrication difficulties.
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