EP0383231A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Fiber optic gyroscope
Assignee: Japan Aviation Electronics Industry Ltd
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Filing: 1990-02-12
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Granted: —
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Expires: 2010-02-12
Abstract
Abstract In a fiber optic gyroscope in which light from a light source (22) is split into two beams for supply to one and the other end of an optical fiber coil (21) respectively, and the two beams having propagated through the optical fiber coil (21) and emitted the one and the other end thereof are coupled together for supply to a photodetector (23), there are separately formed on an optical integrated circuit substrate (30) two optical waveguide couplers (31, 32) , each comprising a trunk (31c, 32c) and a pair of branches (31a, 31b, 32a, 32b) extending therefrom. The pair of branches of a first one of the two optical waveguide couplers (32) are connected to the light source (22) and the photodetector (23), respectively, and the pair of branches of the second optical waveguide coupler (31) are connected to the one and the other end of the optical fiber coil (21), respectively. The trunks of the first and second optical waveguide couplers are interconnected via a connecting optical fiber (35). The optical integrated circuit substrate (30) is fixed to a reinforcing plate of a material which has a thermal expansion coefficient nearly equal to that of the optical integrated circuit substrate. The reinforcing plate is held on a support structure by flexible holding means.
Inventors
- 👤 Kazuhiro Sakuma
- 👤 Aritaka Ohno
- 👤 Eiichi Asami
- 👤 Ryoji Kaku
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 08:29
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/72; G01C19/721; G01C19/722; G02; G02B; G02B6/00; G02B6/44; G02B6/4439; G02B6/4457
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
208 words
A fiber optic gyroscope comprising: an optical fiber coil forming a ring interferometer; a light source; a photodetector; and an optical integrated circuit substrate means disposed inside said optical fiber coil and connected to said light source, said photo-detector and both ends of said optical fiber coil; wherein said optical integrated circuit substrate means has formed thereon a first optical waveguide coupler including first and second branches connected at one end to said light source and said photodetector via first and second connecting optical fibers, respectively, and extending substantially in parallel in a first direction but gradually approaching each other and coupled together at the other ends and a first trunk extending from the juncture of said first and second branches in said first direction, and a second optical waveguide coupler including third and fourth branches connected at one end to the one and the other end of said optical fiber coil, respectively, and extending substantially in parallel in a second direction but gradually approaching each other and coupled together at the other ends and a second trunk extending from the juncture of said third and fourth branches in said second direction, said first and second trunks having their free ends interconnected via a third connecting optical fiber.
Claim 2
Dependent Claim
208 words
A fiber optic gyroscope comprising: an optical fiber coil forming a ring interferometer; a light source; a photodetector; and an optical integrated circuit substrate means disposed inside said optical fiber coil and connected to said light source, said photo-detector and both ends of said optical fiber coil; wherein said optical integrated circuit substrate means has formed thereon a first optical waveguide coupler including first and second branches connected at one end to said light source and said photodetector via first and second connecting optical fibers, respectively, and extending substantially in parallel in a first direction but gradually approaching each other and coupled together at the other ends and a first trunk extending from the juncture of said first and second branches in said first direction, and a second optical waveguide coupler including third and fourth branches connected at one end to the one and the other end of said optical fiber coil, respectively, and extending substantially in parallel in a second direction but gradually approaching each other and coupled together at the other ends and a second trunk extending from the juncture of said third and fourth branches in said second direction, said first and second trunks having their free ends interconnected via a third connecting optical fiber.
Claim 3
Dependent Claim
131 words
The fiber optic gyroscope of claim 1 wherein said optical integrated circuit substrate means includes a substantially rectangular electro-optic crystalline plate, said first and second branches are connected at one end to said light source and said photodetector via said first and second connecting optical fibers, respectively, at a first side of said electro-optic crystalline plate, said third and fourth branches are connected at one end to said one end and said other end of said optical fiber coil, respectively, at a second side of said electro-optic crystalline plate opposite said first side thereof, and said free ends of said first and second trunks are connected to the one and the other end of said third connecting optical fiber at said second and first sides of said electro-optic crystalline plate, respectively.
Claim 4
Dependent Claim
130 words
The fiber optic gyroscope of claim 1 wherein said optical integrated circuit substrate means is a substantially rectangular electro-optic crystalline plate, said first and second branches are connected at one end to said light source and said photo-detector via said first and second connecting optical fibers, respectively, at a first side of said electro-optic crystalline plate, said third and fourth branches are connected at one end to said one end and said other end of said optical fiber coil, respectively, at said first side of said electro-optic crystalline plate, and said free ends of said first and second trunks are connected to said one end and said other end of said third connecting optical fiber, respectively, at a second side of said electro-optic crystalline plate opposite said first side thereof.
Claim 5
Dependent Claim
24 words
The fiber optic gyroscope of claim 1, 2, or 3 wherein said light source and said photodetector are disposed inside said optical fiber coil.
Claim 6
Dependent Claim
60 words
The fiber optic gyroscope of claim 1, 2, or 3 wherein said optical integrated circuit substrate means is fixed to a reinforcing plate of a material having a thermal expansion coefficient substantially equal to that of said optical integrated circuit substrate means, said reinforcing plate being held by flexible holding means on a support structure inside said optical fiber coil.
Claim 7
Dependent Claim
34 words
The fiber optic gyroscope of claim 5 wherein said flexible holding means is an adhesive whereby said reinforcing plate is elastically bonded to the top of said support structure at a plurality of places.
Claim 8
Dependent Claim
62 words
The fiber optic gyroscope of claim 5 wherein said flexible holding means has at least two thin plate-like support pieces protrusively provided on the top of said support structure in opposed relation to at least two opposite sides of said reinforcing plate, and said reinforcing plate is disposed between said two thin plate-like support pieces and is bonded thereto with an adhesive.
Claim 9
Dependent Claim
44 words
The fiber optic gyroscope of claim 7 wherein a bed shorter than said two thin plate-like support pieces is protrusively provided on the top of said support structure between said two thin plate-like support pieces, and said reinforcing plate is mounted on said bed.
Claim 10
Dependent Claim
29 words
A fiber optic gyroscope of any of claims 5 to 8, wherein said reinforcing plate is made of the same material as that of said optical integrated circuit substrate.
Claim 11
Dependent Claim
133 words
A fiber optic gyroscope which includes: a light source, an optical fiber coil; a photodetector; and an optical integrated circuit substrate having formed thereon an optical waveguide whereby light from said light source is split into two for supply to one and the other ends of said optical fiber coil and two rays of light having propagated through said optical fiber coil and emitted from said one end and said other end thereof are coupled together for supply to said photodetector; the improvement comprising: a support structure; a reinforcing plate of a material having a thermal expansion coefficient nearly equal to that of said optical integrated circuit substrate, said reinforcing plate having fixed thereto said optical integrated circuit substrate; and flexible holding means for displaceably holding said reinforcing plate on said support structure.
Claim 12
Dependent Claim
133 words
A fiber optic gyroscope which includes: a light source, an optical fiber coil; a photodetector; and an optical integrated circuit substrate having formed thereon an optical waveguide whereby light from said light source is split into two for supply to one and the other ends of said optical fiber coil and two rays of light having propagated through said optical fiber coil and emitted from said one end and said other end thereof are coupled together for supply to said photodetector; the improvement comprising: a support structure; a reinforcing plate of a material having a thermal expansion coefficient nearly equal to that of said optical integrated circuit substrate, said reinforcing plate having fixed thereto said optical integrated circuit substrate; and flexible holding means for displaceably holding said reinforcing plate on said support structure.
Claim 13
Dependent Claim
36 words
The fiber optic gyroscope of claim 10 said flexible holding means includes an adhesive of the rubber series for elastically bonding said reinforcing plate to the top of said support structure at a plurality of places.
Claim 14
Dependent Claim
62 words
The fiber optic gyroscope of claim 10 wherein said flexible holding means includes at least two thin plate-like support pieces protrusively provided on the top of said support structure in opposed relation to at least two opposite sides of said reinforcing plate, and said reinforcing plate is disposed between said two thin plate-like support pieces and is bonded thereto with an adhesive.
Claim 15
Dependent Claim
44 words
The fiber optic gyroscope of claim 12 wherein a bed shorter than said two thin plate-like support pieces is protrusively provided on the top of said support structure between said two thin plate-like support pieces, and said reinforcing plate is mounted on said bed.
Claim 16
Dependent Claim
25 words
The fiber optic gyroscope of claim 10 wherein said reinforcing plate is formed of the same material as that for said optical integrated circuit substrate.
References Cited (Backward Citations)
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