Waveguide-based Bragg gratings with spectral sidelobe suppression and method thereof
First Claim
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1. A system comprising:
- an optical signal source; and
an integrated circuit operatively coupled to the optical signal source, the integrated circuit including;
a substrate, anda plurality of regions formed in the substrate and having refractive indices different from that of the substrate, each of the plurality of regions separated by intervening areas of the substrate to form a grating, the grating having grating periods with substantially constant pitch, wherein each of the grating periods includes one of the plurality of regions and one of the intervening areas of the substrate, wherein consecutive ones of the plurality of regions have different widths and consecutive ones of the intervening areas have different widths; and
an optical path formed within the substrate passing through the plurality of regions and the intervening areas of the substrate.
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Abstract
A waveguide Bragg grating (WBG) is apodized by varying the duty cycle of selected grating periods while fixing the pitch of the grating periods. In one embodiment, the WBG is implemented in a silicon substrate using polysilicon filled trenches of varying width while keeping the grating periods'"'"' pitch constant. The polysilicon trenches are formed so that if the width of one trench is increased compared to an adjacent grating period, the trench width in the other adjacent grating period (if present) is decreased.
81 Citations
14 Claims
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1. A system comprising:
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an optical signal source; and an integrated circuit operatively coupled to the optical signal source, the integrated circuit including; a substrate, and a plurality of regions formed in the substrate and having refractive indices different from that of the substrate, each of the plurality of regions separated by intervening areas of the substrate to form a grating, the grating having grating periods with substantially constant pitch, wherein each of the grating periods includes one of the plurality of regions and one of the intervening areas of the substrate, wherein consecutive ones of the plurality of regions have different widths and consecutive ones of the intervening areas have different widths; and an optical path formed within the substrate passing through the plurality of regions and the intervening areas of the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method, comprising:
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propagating an optical signal through a Xth region of a plurality of regions formed in a substrate, the plurality of regions having refractive indices different from that of the substrate, each of the plurality of regions separated by intervening areas of the substrate to form a grating, the grating having grating periods with substantially constant pitch, wherein each of the grating periods includes one of the plurality of regions and one of the intervening areas of the substrate, wherein consecutive ones of the plurality of regions have different widths and consecutive ones of the intervening areas have different widths; and propagating the optical signal through a Yth intervening area of the intervening areas of the substrate, the Yth intervening area being adjacent to the Xth region of the plurality of regions formed in the substrate. - View Dependent Claims (13, 14)
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Specification