| 摘要 |
A waveguide structure which is implemented in silica and doped silica includes at least one path region (53) and a confining region (52,54,55). The confining region (52,54,55) is in two regions. The first region (52,54), which is preferably formed of undoped silica and deposited by chemical vapour deposition so that it is never melted, surrounds the path region (53). The second region (55) is doped with a melting point depressant so that it has a lower melting point than the first region (52,54). The first region(52,54) provides a stabilising skeleton when complicated structures. The use of a skeleton facilitates the preparation of 3-dimensional waveguides with path regions which share a common confining region, preferably of uniformed refractive index. The path regions may be located at two or more different levels. <IMAGE> |
