| 摘要 |
A method for forming a waveguide (200) having a thin-core region, a thick-core region, and a transition region of tapered thickness between them is disclosed. The method comprises forming a lower core layer (214) of a first material on a lower cladding (212), forming a thin central core layer (216) of a second material on the first core layer (214), forming an upper core layer (218) of the first material on the central core layer (216), and etching the upper core layer (218) in an etchant such that it is removed from the thin-core region and its thickness monotonically changes from its as-deposited thickness (t4) to extinction across the transition region, where the central core layer (216)protects the lower core layer (214) from exposure to the etchant. |
