Patent US4420260A successfully refreshed from Google Patents.
US4420260A
Expired / Lapsed
US
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Interferometer transmitting the useful phase information through optical fibres
Assignee: CISE Centro Informazioni Studi e Esperienze SpA
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Filing: 1982-05-04
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Granted: 1983-12-13
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Expires: 2002-05-04
Abstract
Abstract The invention relates to an inerferometer based on the exploitation of an optical fibre through which both the phase signal which is of interest for the measurements concerned and a reference signal are simultaneously forwarded in order that in the differential measurement the noise introduced by the optical fibre for both thermal and mechanical reasons is ruled out.
Inventors
- 👤 Mario Martinelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:49
CPC Classifications
G; G01; G01J; G01J9/00; G01J9/02; G01H; G01H9/00; G01H9/004; G01H9/006; G01J2009/0226
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
126 words
An optical-fibre interferometer with differential substraction of the noise collected by the optical-fibre transmission line, characterized in that it comprises a laser-light emitter which sends a beam of polarized light to the input end of a single-mode optical fibre, at the output end whereof a first beam splitter is provided which directs the two resultant beams onto a reference mirror and onto a device which produces a reflection of the beam with modulation of the optical phase to be detected, respectively, the two reflected beams coming from the device and the reference mirror being fed back through said first splitter to said output end of the optical fibre to form a composite beam sent from said input end of the optical fibre to a detecting element.
Claim 2
Dependent Claim
126 words
An optical-fibre interferometer with differential substraction of the noise collected by the optical-fibre transmission line, characterized in that it comprises a laser-light emitter which sends a beam of polarized light to the input end of a single-mode optical fibre, at the output end whereof a first beam splitter is provided which directs the two resultant beams onto a reference mirror and onto a device which produces a reflection of the beam with modulation of the optical phase to be detected, respectively, the two reflected beams coming from the device and the reference mirror being fed back through said first splitter to said output end of the optical fibre to form a composite beam sent from said input end of the optical fibre to a detecting element.
Claim 3
Dependent Claim
47 words
Interferometer according to claim 1, characterized in that it comprises a second beam splitter inserted between said laser-light emitter and said input end of the optical fibre to give a free way to said polarized light beam and to send said composite beam to said detecting element.
Claim 4
Dependent Claim
32 words
Interferometer according to claim 2, characterized in that said light beam is linearly polarized prior to being passed through said second beam splitter and is subsequently circularly polarized through a quarter-wavelength lamina.
Claim 5
Dependent Claim
23 words
Interferometer according to claim 1, characterized in that said optical fibre is combined with optical assemblies both at the input and the output.
Claim 6
Dependent Claim
22 words
Interferometer according to claim 1, characterized in that said device for reflecting the beam with phase modulation consists of a vibratory mirror.
Claim 7
Dependent Claim
32 words
Interferometer according to claim 1, characterized in that said polarized light beam consists of two discrete beams having mutually orthogonal polarization and said first beam splitter consists of a polarizing beam splitter.
Claim 8
Dependent Claim
25 words
Interferometer according to claim 6, characterized in that it comprises a delay half-wavelength lamina inserted between said optical fibre input end and said detecting element.
Claim 9
Dependent Claim
25 words
Interferometer according to claim 1, characterized in that it comprises a diverging optical element placed in correspondence with said input end of said optical fibre.
Claim 10
Dependent Claim
32 words
Interferometer according to claim 8, characterized in that said composite beam is sent to said detecting element via a perforated mirror inserted between said optical fibre input end and said laser-light emitter.
Claim 11
Dependent Claim
21 words
Interferometer according to claim 8, characterized in that said detecting element consists of a plurality of photodetectors arranged along an annulus.
Claim 12
Dependent Claim
20 words
Interferometer according to claim 1, characterized in that said first beam splitter is composed of mutually coupled single-mode optical fibres.
Claim 13
Dependent Claim
18 words
Interferometer according to claim 1, characterized in that said first beam splitted is constructed with integrated optical technology.
Claim 14
Dependent Claim
18 words
Interferometer according to claim 1, characterized in that said first beam splitter is constructed with discrete optical elements.
References Cited (Backward Citations)
GB1373645A
Cited
US4153370A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-12 | 1987-06-13 | 1987-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-12 | 1991-06-13 | 1991-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-12 | 1995-06-13 | 1995-12-13 | $7700.00 | Window Closed / Lapsed |