US3625619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refraction-measuring apparatus utilizing common optical modulator
Assignee: Linde Sverige AB
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Filing: 1970-03-27
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Granted: 1971-12-07
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Expires: 1990-03-27
Abstract
Abstract Modulated light containing components of two different wavelengths is transmitted over a path and the modulation phase difference at the receiving end of the path is determined. A common optical modulator is used for demodulating both of the received light components in order to minimize differences in phase between these two components.
Inventors
- 👤 Karl Otto Ragnar Scholdstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:17
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
174 words
In a refraction-measuring apparatus comprising, means for emitting a beam of light having a first component of a first wavelength and a second component of a second wavelength along a predetermined path, first modulator means for modulating said first and second components with a first modulating signal of a first frequency, and means for measuring the modulation phase difference between said first and second components after said components have traversed said path, wherein the improvement comprises means for reducing phase error between said components, said means comprising second modulator means for commonly modulating said first and second components after said components have traversed said path with a frequency different from said first frequency, optical separating means for receiving the output of said second modulator and for optically separating said output into said first and second components, means for receiving said first and second components after said components have been separated in said optical separating means and for producing output signals in accordance with said components, and phase responsive means for receiving said output signals.
Claim 2
Dependent Claim
174 words
In a refraction-measuring apparatus comprising, means for emitting a beam of light having a first component of a first wavelength and a second component of a second wavelength along a predetermined path, first modulator means for modulating said first and second components with a first modulating signal of a first frequency, and means for measuring the modulation phase difference between said first and second components after said components have traversed said path, wherein the improvement comprises means for reducing phase error between said components, said means comprising second modulator means for commonly modulating said first and second components after said components have traversed said path with a frequency different from said first frequency, optical separating means for receiving the output of said second modulator and for optically separating said output into said first and second components, means for receiving said first and second components after said components have been separated in said optical separating means and for producing output signals in accordance with said components, and phase responsive means for receiving said output signals.
Claim 3
Dependent Claim
40 words
An apparatus as claimed in claim 1 wherein said phase responsive means comprises a null instrument responsive to the phase difference between said first and second received components, said apparatus further including means for adjustably delaying one of said components.
Claim 4
Dependent Claim
16 words
An apparatus as claimed in claim 2 wherein said first and second modulators are Pockels-type modulators.
References Cited (Backward Citations)
US3200698A
Cited
US3409369A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |