| 摘要 |
Planar lightwave circuits (PLCs) are typically provided with a passivation coating layer to prevent damaging effects of environmental factors. In certain cases, deep trenching or a similar procedure after passivation removes the protective passivation coating, exposing the underlying layers. Without the passivation coating, the exposed core and cladding layers may absorb moisture resulting in an unacceptable shift in their refractive index. A supplemental hermetic sealing technique suitable for use in localized areas of a PLC, e.g., in areas where passivation may have been removed, consists of providing a sealing lid having a sealing surface, and diffusion-bonding the sealing surface of the sealing lid to the bonding surface about the PLC area. Preferably, prior to said diffusion bonding, the upper bonding surface about the PLC area and the sealing surface of the sealing lid are smoothed to facilitate the bonding.
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