US4288785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light intensity modulator with digital control and a digital-analog converter comprising such a modulator
Assignee: Thales SA
•
Filing: 1980-05-20
•
Granted: 1981-09-08
•
Expires: 2000-05-20
Abstract
Abstract The invention relates to a light intensity modulator controlled by a "word" of n bits and an opto-electronic digital-analog converter. The modulator comprises a two-arm interferometer in whose length there is created, by opto-electrical effect, successive phase shifts controlled respectively by control bits and whose values, when the control bits are in state 1, conform to the successive powers of 2. The total phase shift obtained thus depends directly on the analog value of the control word and the emerging intensity is modulated as a function of this word. A digital-analog converter is constructed by adding a photodetector means whose output voltage depends on the analog value of the control word.
Inventors
- 👤 Michel Papuchon
- 👤 Claude Puech
- 👤 Jean C. Anne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:34
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/21; G02F1/225; G02F7/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
113 words
A digitally controlled light intensity modulator comprising, on the surface of a substrate having electro-optical properties, a two-arm interferometer connected to an input guide receiving incident optical radiation, the fractions of radiation propagated in the two arms combining at the output of the interferometer in an output guide, the intensity of the emerging radiation depending on the phase shift introduced into the interferometer between the fractions of radiation propagated in the two arms, wherein the phase shift is the sum of n elementary phase shifts successively created along the interferometer respectively by n digital control voltages, these n elementary phase shifts being produced in conformity with a geometrical progression of common ratio 2.
Claim 2
Dependent Claim
113 words
A digitally controlled light intensity modulator comprising, on the surface of a substrate having electro-optical properties, a two-arm interferometer connected to an input guide receiving incident optical radiation, the fractions of radiation propagated in the two arms combining at the output of the interferometer in an output guide, the intensity of the emerging radiation depending on the phase shift introduced into the interferometer between the fractions of radiation propagated in the two arms, wherein the phase shift is the sum of n elementary phase shifts successively created along the interferometer respectively by n digital control voltages, these n elementary phase shifts being produced in conformity with a geometrical progression of common ratio 2.
Claim 3
Dependent Claim
37 words
The modulator as claimed in claim 1, wherein an adjustable DC source is provided for creating a constant phase shift, so that the emerging intensity is minimum when all the digital control voltages are in state 0.
Claim 4
Dependent Claim
39 words
The modulator as claimed in claim 2, wherein the DC voltage is applied between a common grounded electrode for all the control voltages and a polarizing electrode placed in the vicinity of one of the forks of the interferometer.
Claim 5
Dependent Claim
39 words
The modulator as claimed in claim 2, wherein the n control voltages are applied between a common grounded electrode, on the one hand, and respectively at least n electrodes placed on the same side with respect to the arms.
Claim 6
Dependent Claim
31 words
The modulator as claimed in claim 4, wherein the n electrodes have lengths in a geometric progression of common ratio 2, the n control voltages being applied directly to the electrodes.
Claim 7
Dependent Claim
42 words
The modulator as claimed in claim 4, wherein the n electrodes have the same length and wherein the n control voltages are applied to n electrodes through n voltage dividers whose dividing ratios are in a geometric progression of common ratio 2.
Claim 8
Dependent Claim
57 words
A digital-analog converter supplying an output voltage corresponding to the analog value associated with a control word formed from n digital voltages, comprising a modulator such as claimed in claim 6, controlled by these n digital voltages, and photodetector means collecting at least a fraction of the intensity of the emerging radiation and supplying said output voltage.
Claim 9
Dependent Claim
47 words
The modulator as claimed in claim 1, wherein there is further provided a feedback loop receiving a part of the radiation emerging into the output guide, and inducing n feedback phase shifts which are respectively superimposed on the n phase shifts created by the digital control voltages.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |