US3896398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Driver circuit for pulse modulation of a semiconductor laser
Assignee: NEC Corp
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Filing: 1973-11-05
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Granted: 1975-07-22
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Expires: 1993-11-05
Abstract
Abstract A pulse modulation driver circuit for a semiconductor laser is disclosed which discriminates among input pulse signals composed of binary codes to detect the occurrence of a pulse having a code of '''' 1'''' following a pulse having a code of ''''0''''. Detection of this pattern is used to control the driver to increase either or both the width or peak value of the pulse having a code of 1. The effect of this is to eliminate a pattern effect in the light emitted by the semiconductor laser caused by an attenuation of the population inversion in the laser.
Inventors
- 👤 Atsufumi Ueki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:17
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/062; H01S5/06209; H01S5/06216; G; G02; G02F; G02F3/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
135 words
A pulse modulation driver circuit for a semiconductor laser, comprising: a. means for receiving input pulse signals composed of binary codes wherein the code for the presence of output light of the laser is 1 while the code for the absence of light is 0; b. means connected to said receiving means for discriminating among the input pulse signals to detect the occurrence of a pulse having a code of 1 following a pulse having a code of 0; c. means connected to said receiving means and controlled by said discriminating means for modulating the detected pulse to increase the average driving current to said laser whereby the intensity of an output light pulse of said semiconductor laser corresponding to a pulse signal having a code of 1 is independent of a preceding pulse signal.
Claim 2
Dependent Claim
135 words
A pulse modulation driver circuit for a semiconductor laser, comprising: a. means for receiving input pulse signals composed of binary codes wherein the code for the presence of output light of the laser is 1 while the code for the absence of light is 0; b. means connected to said receiving means for discriminating among the input pulse signals to detect the occurrence of a pulse having a code of 1 following a pulse having a code of 0; c. means connected to said receiving means and controlled by said discriminating means for modulating the detected pulse to increase the average driving current to said laser whereby the intensity of an output light pulse of said semiconductor laser corresponding to a pulse signal having a code of 1 is independent of a preceding pulse signal.
Claim 3
Dependent Claim
53 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 1 wherein said modulating means increases the width of said detected pulse sufficient to cause a population inversion in said semiconductor laser that results in a uniform light output for every input pulse signal having the code of 1 .
Claim 4
Dependent Claim
74 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 2 wherein said discriminating means comprises: a. delay means connected to said receiving means for delaying said input pulse signals by one pulse period; b. inverting means connected to the output of said delay means; and c. an AND circuit means connected to receive as inputs the input pulse signals from said receiving means and the output of said inverting means.
Claim 5
Dependent Claim
63 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 3 wherein said modulation means comprises: a. second delay means connected to said receiving means for delaying said input pulse signals by less than one pulse period; and b. an OR circuit means connected to receive as inputs the outputs of said second delay means and said AND circuit means.
Claim 6
Dependent Claim
36 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 1 further comprising an amplifying means connected to receive the output of said modulating means for providing driving current to said semiconductor laser.
Claim 7
Dependent Claim
53 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 1 wherein said modulating means increases the peak value of said detected pulse sufficient to cause a population inversion in said semiconductor laser that results in a uniform light output for every input pulse signal having the code of 1.
Claim 8
Dependent Claim
56 words
A pulse modulation driver circuit for a semiconductor laser as recited in claim 1 wherein said modulating means increases both the width and peak value of said detected pulse sufficient to cause a population inversion in said semicondcutor laser that results in a uniform light output for every input pulse signal having the code of 1.
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) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |