Athermal fiber Bragg grating
First Claim
1. An athermal fiber Bragg grating assembly, comprising:
- a platform of a first material having a first coefficient of thermal expansion (α
1) between first and second attachment locations defining an attachment-length (L1) there between;
a stick of a second material having a second coefficient of thermal expansion (α
2) between first and second ends defining a stick-length (L2) there between; and
a fiber Bragg type grating of a third material having an effective third coefficient of thermal expansion (α
3) between first and second ends defining a grating-length (L3) there between, wherein said effective third coefficient (α
3) is based on a combination of thermal expansion and refractive index variation in said grating with respect to temperature; and
wherein;
said second end of said stick is fixed to said first end of said grating, said first end of said stick is fixed to said first attachment location, and said second end of said grating is fixed to said second attachment location;
said stick has an essentially same cross-sectional stick-area exhibited along said stick-length, said grating has a cross-sectional grating-area at its said first end, and said stick-area is equal to or less than said grating-area; and
said coefficients (α
1, α
2, and α
3) and said lengths (L1, L2, and L3) are such that the assembly exhibits an effective overall coefficient of thermal expansion (α
ALL) in accord with the equation;
α
ALL=(α
1*L1+α
3*L3−
α
2*L2)/L3≈
0.
1 Assignment
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Accused Products
Abstract
An a thermal fiber Bragg grating assembly. A platform provides two attachment locations and has a first coefficient of thermal expansion. A stick provides two ends and has a second coefficient of thermal expansion. A fiber Bragg grating provides two ends and has effective third coefficient of thermal expansion. One stick end is fixed to one grating end, the other stick end is fixed to one attachment location, and the other grating end is fixed to the other attachment location. The stick has a same cross-section area along its length that is equal to or less than the cross-section area of the grating. And the coefficients and lengths between respective locations and ends are such that the assembly exhibits an effective overall coefficient of thermal expansion approaching zero.
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Citations
20 Claims
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1. An athermal fiber Bragg grating assembly, comprising:
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a platform of a first material having a first coefficient of thermal expansion (α
1) between first and second attachment locations defining an attachment-length (L1) there between;a stick of a second material having a second coefficient of thermal expansion (α
2) between first and second ends defining a stick-length (L2) there between; anda fiber Bragg type grating of a third material having an effective third coefficient of thermal expansion (α
3) between first and second ends defining a grating-length (L3) there between, wherein said effective third coefficient (α
3) is based on a combination of thermal expansion and refractive index variation in said grating with respect to temperature; and
wherein;said second end of said stick is fixed to said first end of said grating, said first end of said stick is fixed to said first attachment location, and said second end of said grating is fixed to said second attachment location; said stick has an essentially same cross-sectional stick-area exhibited along said stick-length, said grating has a cross-sectional grating-area at its said first end, and said stick-area is equal to or less than said grating-area; and said coefficients (α
1, α
2, and α
3) and said lengths (L1, L2, and L3) are such that the assembly exhibits an effective overall coefficient of thermal expansion (α
ALL) in accord with the equation;
α
ALL=(α
1*L1+α
3*L3−
α
2*L2)/L3≈
0. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for athermalizing a fiber Bragg grating, comprising:
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providing a platform of a first material having a first coefficient of thermal expansion (α
1) between first and second attachment locations defining an attachment-length (L1) there between;providing a stick of a second material having a second coefficient of thermal expansion (α
2) between first and second ends defining a stick-length (L2) there between;defining the grating as being of a third material having an effective third coefficient of thermal expansion (α
3) between first and second ends defining a grating-length (L3) there between, wherein said effective third coefficient (α
3) is based on a combination of thermal expansion and refractive index variation in the grating with respect to temperature;affixing said second end of said stick to said first end of the grating, affixing said first end of said stick to said first attachment location, and affixing said second end of the grating to said second attachment location; providing that said stick has an essentially same cross-sectional stick-area exhibited along said stick-length, that the grating has a cross-sectional grating-area at its said first end, and that said stick-area is equal to or less than said grating-area; and providing that said coefficients (α
1, α
2, and α
3) and said lengths (L1, L2, and L3) are such that a resulting assembly of the grating, said stick, and said platform exhibit an effective overall coefficient of thermal expansion (α
ALL) in accord with the equation;
α
ALL=(α
1*L1+α
3*L3−
α
2*L2)/L3≈
0. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An athermal fiber Bragg grating assembly, comprising:
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platform means for providing first and second attachment locations defining an attachment-length (L1) there between, wherein said platform means is of a first material having a first coefficient of thermal expansion (α
1);stick means for providing first and second ends defining a stick-length (L2) there between, wherein said stick means is of a second material having a second coefficient of thermal expansion (α
2); anda fiber Bragg type grating having first and second ends defining a grating-length (L3) there between, wherein said grating is of a third material having an effective third coefficient of thermal expansion (α
3) that is based on a combination of thermal expansion and refractive index variation in said grating with respect to temperature; and
wherein;said second end of said stick means is fixed to said first end of said grating, said first end of said stick means is fixed to said first attachment location, and said second end of said grating is fixed to said second attachment location; said stick means has an essentially same cross-sectional stick-area exhibited along said stick-length, said grating has a cross-sectional grating-area at its said first end, and said stick-area is equal to or less than said grating-area; and said coefficients (α
1, α
2, and α
3) and said lengths (L1, L2, and L3) are such that the assembly exhibits an effective overall coefficient of thermal expansion (α
ALL) in accord with the equation;
α
ALL=(α
1*L1+α
3* L3−
α
2*L2)/L3≈
0. - View Dependent Claims (19, 20)
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Specification