Method for fabricating planar optical waveguide devices
First Claim
1. A method for fabricating a planar optical waveguide device having a plurality of core segments formed between a lower clad layer and an upper clad layer, comprising the steps of:
- providing a lower clad layer;
forming a recess corresponding to a desired pattern of core segments in said lower clad layer;
forming a core layer on said lower clad layer including an interior of said recess;
conducting a hot isostatic pressing process on an assembly of said lower clad layer and said core layer at a temperature higher than 800°
C. and a pressure higher than 1,000 kgf/cm2;
removing a surface layer from an assembly of said lower clad layer and said core layer until a surface of said lower clad layer is exposed, and said lower clad layer and said core layer in said recess jointly define a planar surface; and
forming an upper clad layer on said planar surface jointly defined by said lower clad layer and said core layer.
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Accused Products
Abstract
Proposed is a method for fabricating a planar optical waveguide device having a plurality of core segments formed between a lower clad layer and an upper clad layer, in which a hot isostatic pressing process (HIP) is carried out during the fabrication process. The lower clad layer may consist of a substrate or a buffer layer formed on a substrate. Each layer may be formed either by a low-temperature film-forming process such as CVD or by the flame hydrolysis pressing process. The HIP process is also effective in eliminating voids when the core is formed in a recess of the lower clad layer. According to the tests conducted by the inventors, it was found that the HIP process can be conducted without requiring any protective layer or a gas barrier through proper selection of the condition for the HIP process, as opposed to the common belief that a protective layer or a gas barrier is essential for the HIP process.
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Citations
7 Claims
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1. A method for fabricating a planar optical waveguide device having a plurality of core segments formed between a lower clad layer and an upper clad layer, comprising the steps of:
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providing a lower clad layer;
forming a recess corresponding to a desired pattern of core segments in said lower clad layer;
forming a core layer on said lower clad layer including an interior of said recess;
conducting a hot isostatic pressing process on an assembly of said lower clad layer and said core layer at a temperature higher than 800°
C. and a pressure higher than 1,000 kgf/cm2;
removing a surface layer from an assembly of said lower clad layer and said core layer until a surface of said lower clad layer is exposed, and said lower clad layer and said core layer in said recess jointly define a planar surface; and
forming an upper clad layer on said planar surface jointly defined by said lower clad layer and said core layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification