US4659223A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photorefractive crystal interferometric device for measuring an angular rotational speed
Assignee: Thales SA
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Filing: 1984-11-01
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Granted: 1987-04-21
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Expires: 2004-11-01
Abstract
Abstract An interferometric device for measuring an angular rotational speed comprising an amplifying photo refractive crystal placed in the path of optical guide means forming a closed loop. Two signal waves penetrate into said crystal so as to obtain two contrarotating waves of different optical frequencies and of amplitudes restored by amplification in the crystal, moving in said closed loop.
Inventors
- 👤 Jean-Pierre Huignard
- 👤 Herve Arditty
- 👤 Claude Puech
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:37
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/72
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
An interferometric device for measuring an angular rotational speed, comprising: optical guide means forming a closed loop in which two contrarotating waves travel; a photorefractive crystal disposed in the path of a leg of said closed loop; means for generating an electric field in said photorefractive crystal; means for interfering two opposed pump waves with said contrarotating waves in said photorefractive crystal, said opposing pump waves being non-colinear and angled with respect to said path at said leg by angles having opposite senses, whereby energy is transferred from said pump waves to said contrarotating waves; means for mixing said contrarotating waves; and means for detecting said mixed waves.
Claim 2
Dependent Claim
108 words
An interferometric device for measuring an angular rotational speed, comprising: optical guide means forming a closed loop in which two contrarotating waves travel; a photorefractive crystal disposed in the path of a leg of said closed loop; means for generating an electric field in said photorefractive crystal; means for interfering two opposed pump waves with said contrarotating waves in said photorefractive crystal, said opposing pump waves being non-colinear and angled with respect to said path at said leg by angles having opposite senses, whereby energy is transferred from said pump waves to said contrarotating waves; means for mixing said contrarotating waves; and means for detecting said mixed waves.
Claim 3
Dependent Claim
37 words
The device as claimed in claim 1, wherein said guide means comprise at least three flat mirrors whose reflecting surfaces are disposed towards the inside of the loop, one of said mirrors being a semi transparent mirror.
Claim 4
Dependent Claim
20 words
The device as claimed in claim 2, wherein one of said mirrors is a mirror made from a piezoelectric material.
Claim 5
Dependent Claim
15 words
The device as claimed in claim 1, wherein said guide means comprise an optical fiber.
Claim 6
Dependent Claim
28 words
The device as claimed in claim 1 including a phase modulator disposed in a path of one of said pump waves before said pump wave reached said crystal.
Claim 7
Dependent Claim
16 words
The device as claimed in claim 1, wherein said crystal is disposed in a laser cavity.
Claim 8
Dependent Claim
15 words
The device as claimed in claim 1, wherein said crystal is a bismuth-silicon oxide crystal.
Claim 9
Dependent Claim
15 words
The device as claimed in claim 1, wherein said crystal is made from barium titanate.
Claim 10
Dependent Claim
39 words
The device of claim 1 wherein said means for interfering comprise: a laser; and a prism including surfaces positioned for splitting a beam from said laser and directing said split beam into said crystal to form said pump waves.
References Cited (Backward Citations)
US3581227A
Cited
US4396290A
Cited
US4344706A
Cited
US4405236A
Cited
FR2500937A1
Cited
EP0079268A1
Cited
US4525843A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |