US3614447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for modulating semiconductor lasers
Assignee: AT&T Inc
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Filing: 1969-06-16
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Granted: 1971-10-19
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Expires: 1989-06-16
Abstract
Abstract A semiconductor junction laser is modulated by applying a suitable DC voltage to produce self-induced pulsing, phase locking the pulsing repetition rate to a low-power microwave signal, and modulating the microwave signal. Information carrying capacities in excess of 10 megahertz are obtained with microwave power of a few milliwatts. Multiplexing arrangements are also described.
Inventors
- 👤 Thomas L Paoli
- 👤 Jose E Ripper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:49
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/062; H01S5/06209; H01S5/06216
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
13 words
The method according to claim 1 wherein said locking signal is frequency modulated.
Claim 2
Dependent Claim
44 words
The method according to claim 2 wherein: said semiconductor laser is a PN junction laser; said spontaneous pulsing is induced by the application of a DC voltage; and said phase locking of the pulsing repetition rate is produced by a microwave frequency voltage source.
Claim 3
Dependent Claim
16 words
The method according to claim 3 wherein said semiconductor laser is a gallium arsenide junction laser.
Claim 4
Dependent Claim
70 words
Apparatus for producing a modulated light signal comprising: a PN junction laser; means for applying a DC voltage to said laser of sufficient value to produce self-induced pulsing in the laser output; means for applying a low-power microwave signal to said laser to lock the repetition rate of said pulses to the frequency of said microwave signal; and means for modulating said microwave signal in accordance with an information-carrying signal.
Claim 5
Dependent Claim
108 words
A multiplexed communications system comprising: a plurality of PN junction lasers; means for applying DC voltage to each of said lasers to produce self-induced pulsing of each of said lasers at approximately the same repetition rate; means for applying a low-power microwave signal to each of said lasers to lock the repetition rate of said pulses to substantially the same value; and means for separately modulating the microwave signals applied to each of said lasers in accordance with an information-carrying signal; means for introducing sufficient phase differences among the separately modulated lasers that the modulated pulses do not overlap; and means for receiving the light from said lasers.
Claim 6
Dependent Claim
37 words
A multiplexed communications system comprising: a plurality of units of apparatus according to claim 5 the lasers comprising two or more groups emitting resolvably different frequencies of light; and means for receiving the light from said lasers.
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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |