| 摘要 |
<p>A planar optical waveguiding device comprises a core (10) located adjacent to one or between empty grooves which extend both above and below the core (10). Preferably the core (10) has a bend with a radius of curvature of less than 2mm. and the empty grooves (11 and 12) are located inside and outside the bend with interfaces (15, 16) with the core (10). Since the grooves (11, 12) are prepared by etching they will normally extend to the surface of the device but it is necessary to continue the etching below the bottom of the core (10) in order to achieve satisfactory guidance. The use of 'empty' grooves permit tighter bends so that more devices, e.g. arrayed waveguide grating devices, can be produced on a wafer of a given size. An embodiment using a core (82) between two grooves (85, 86) with a heating element (87) as part of a Mach-Zehnder device is claimed.</p> |
