Low-loss waveguide and method of making same
First Claim
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1. A method of making a low-loss high index difference waveguide having silicon as its core, comprising:
- providing a planar strip waveguide having core/cladding interface roughness; and
subjecting said waveguide to one or more reactions so that one of said reactions produces reaction products with different chemical compositions from that of said core and reduce the core/cladding interface root-mean-square (RMS) roughness in order to in turn reduce scattering losses in said waveguide, wherein the effective index difference between said core and cladding is above 0.1, said reaction products having graded refractive index profiles from that of the core to that of the cladding.
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Abstract
A method of reducing the scattering losses that involves smoothing of the core/cladding interface and/or change of waveguide geometry in high refractive index difference waveguides. As an example, the SOI-based Si/SiO2 waveguides are subjected to an oxidation reaction at high temperatures, after the waveguide patterning process. By oxidizing the rough silicon core surfaces after the patterning process, the core/cladding interfaces are smoothened, reducing the roughness scattering in waveguides.
58 Citations
43 Claims
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1. A method of making a low-loss high index difference waveguide having silicon as its core, comprising:
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providing a planar strip waveguide having core/cladding interface roughness; and
subjecting said waveguide to one or more reactions so that one of said reactions produces reaction products with different chemical compositions from that of said core and reduce the core/cladding interface root-mean-square (RMS) roughness in order to in turn reduce scattering losses in said waveguide, wherein the effective index difference between said core and cladding is above 0.1, said reaction products having graded refractive index profiles from that of the core to that of the cladding. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of making a low-loss high index difference waveguide, comprising:
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providing a planar waveguide containing core/cladding interface roughness; and
subjecting said waveguide to one or more treatments so that one of said treatments is a reaction that produces reaction products with different chemical compositions from that of the core and reduces the core/cladding interface root-mean-square (RMS) roughness in order to in turn reduce scattering losses in said waveguide, wherein the effective index difference between said core and cladding is above 0.1, said reaction products have graded refractive index profile from that of the core to that of the cladding. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification