US4459547A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for precise measurement of long-term stability of photodetectors
Assignee: United States Department of the Navy
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Filing: 1981-05-01
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Granted: 1984-07-10
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Expires: 2001-05-01
Abstract
Abstract A method and apparatus is disclosed for the measurement of the long-term bility of photodetectors. A fiber optic star coupler divides optical flux from a source of light into highly stable proportioned light outputs. Each of the photodetectors to be tested is connected to be irradiated by one of the star coupler light outputs. Each of at least one reference photodetectors having known stabilities is connected to one of the remaining outputs of the star coupler. Resulting outputs of the photodetectors to be tested are compared against the resulting output from the reference photodetector.
Inventors
- 👤 Stephen A. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:48
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/26; G01R31/2642
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
154 words
A device for testing the stability of M photodetectors by comparing a response characteristic of said M photodetectors to the same response characteristic of at least one reference photodetector comprising: a source of optical flux; means for receiving the optical flux from said source and for dividing said optical flux into N constant proportion optical flux outputs; M photodetectors to be tested, each connected to one of said N outputs, where M<N and M and N are integers; and at least one reference photodetector having known stability, each being connected to one of said N outputs; whereby upon irradiation of each of said M photodetectors to be tested and upon irradiation of each of said at least one reference photodetectors by one of said N constant proportion optical flux outputs, said response characteristic of said M photodetectors to be tested can be compared to said response characteristic of said at least one reference photodetector.
Claim 2
Independent Claim
154 words
A device for testing the stability of M photodetectors by comparing a response characteristic of said M photodetectors to the same response characteristic of at least one reference photodetector comprising: a source of optical flux; means for receiving the optical flux from said source and for dividing said optical flux into N constant proportion optical flux outputs; M photodetectors to be tested, each connected to one of said N outputs, where M<N and M and N are integers; and at least one reference photodetector having known stability, each being connected to one of said N outputs; whereby upon irradiation of each of said M photodetectors to be tested and upon irradiation of each of said at least one reference photodetectors by one of said N constant proportion optical flux outputs, said response characteristic of said M photodetectors to be tested can be compared to said response characteristic of said at least one reference photodetector.
Claim 3
Dependent Claim
19 words
The device of claim 1 wherein each of said reference photodetectors is mounted within a first controlled temperature oven.
Claim 4
Dependent Claim
19 words
The device of claim 2 wherein each of said reference photodetectors is mounted within a second controlled temperature oven.
Claim 5
Independent Claim
16 words
The device of claims 1, 2 or 3 wherein said receiving means comprises a star coupler.
Claim 6
Dependent Claim
18 words
The device of claim 4 wherein said source of optical flux comprises at least one light emitting diode.
Claim 7
Dependent Claim
20 words
The device of claim 5 further comprising: a variable current supply connected to said at least one light emitting diode.
Claim 8
Dependent Claim
31 words
The device of claim 6 further comprising: means for measuring an output characteristic of each of said M photodetectors to be tested and each of said at least one reference photodetectors.
Claim 9
Dependent Claim
23 words
The device of claim 7 wherein said star coupler is connected to said source of optical flux by a first fiber optic link.
Claim 10
Dependent Claim
30 words
The device of claim 8 wherein said star coupler is connected to each of said M photodetectors and to each of said reference photodetectors by a second fiber optic link.
Claim 11
Dependent Claim
11 words
The device of claim 4 wherein M is at least three.
Claim 12
Dependent Claim
13 words
The device of claim 7 wherein said measuring means comprises a current meter.
Claim 13
Independent Claim
63 words
A method of testing the stability of photodetectors comprising: generating a set of N constant proportion optical flux outputs; irradiating each of M photodetectors to be tested with one of said N outputs where M<N; irradiating at least one reference photodetector with one of said N outputs; comparing the output of each of said M photodetectors with the outputs of said reference photodetectors.
Claim 14
Independent Claim
63 words
A method of testing the stability of photodetectors comprising: generating a set of N constant proportion optical flux outputs; irradiating each of M photodetectors to be tested with one of said N outputs where M<N; irradiating at least one reference photodetector with one of said N outputs; comparing the output of each of said M photodetectors with the outputs of said reference photodetectors.
Claim 15
Dependent Claim
11 words
The method of claim 12 wherein N is at least four.
References Cited (Backward Citations)
US3781092A
Cited
US3749924A
Cited
US4147979A
Cited
US4163194A
Cited
US4129823A
Cited
US4122383A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |