US4319203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Performance-stabilization system for an electrical component emitting pulsed energy
Assignee: Telecom Italia SpA
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Filing: 1979-08-15
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Granted: 1982-03-09
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Expires: 1999-08-15
Abstract
Abstract An emitter of unbalanced pulse-modulated energy, specifically a laser, has a feedback circuit including a first branch detecting the mean amplitude of the emitted energy and a second branch detecting the peak amplitude of its pulses. The second branch includes a band-pass filter, centered on the pulse cadence, followed by a peak detector which may comprise a coherent demodulator driven by a square wave whose frequency corresponds to that cadence. The peak detector generates a control signal for a pulse former whose output signals are superimposed upon a biasing signal from the first branch before being fed to the modulating input of the energy emitter.
Inventors
- 👤 Alberto Brosio
- 👤 Vittorio Seano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:41
CPC Classifications
H; H03; H03L; H03L5/00; H01; H01S; H01S5/00; H01S5/06; H01S5/068; H01S5/0683; H01S5/06835; H04; H04B; H04B10/00; H04B10/50; H04B10/501; H04B10/503; H04B10/504
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
290 words
A system for sending out stabilized binary message signals, comprising: a semiconductor laser emitting a beam of radiant energy to an optical fiber upon being excited by a current exceeding a predetermined threshold; pulse-forming means connected to said laser for modulating the emitted energy by a series of randomly alternating low-level and high-level message pulses of predetermined recurrence frequency representing data to be transmitted; extraction means connected to an output of said laser for recovering a fraction of the energy of each emitted message pulse; a band-pass filter connected to said extraction means and provided with a pass band centered on said recurrence frequency; peak-detection means connected to said band-pass filter for generating a feedback signal proportional to the magnitude of the recovered energy fraction of at least some of said high-level message pulses, said peak-detection means comprising a coherent demodulator driven by a train of clock pulses of a cadence equal to said recurrent frequency; a connection extending from said peak-detection means to a control input of said pulse-forming means for stabilizing the amplitude of said high-level message pulses in response to said feedback signal; integrating circuitry connected to said extraction means in parallel with said band-pass filter for averaging the recovered energy fraction; a current generator in cascade with said integrating circuitry deriving from the averaged energy fraction a biasing signal in the form of a reference current slightly exceeding said threshold, said reference current being fed to said laser for establishing a predetermined operating point therefor; and an adder inserted between said pulse-forming means and a driving input of said laser, said adder having an input connected to said current generator for delivering a combination of said biasing signal and said message pulses to said driving input.
Claim 2
Independent Claim
290 words
A system for sending out stabilized binary message signals, comprising: a semiconductor laser emitting a beam of radiant energy to an optical fiber upon being excited by a current exceeding a predetermined threshold; pulse-forming means connected to said laser for modulating the emitted energy by a series of randomly alternating low-level and high-level message pulses of predetermined recurrence frequency representing data to be transmitted; extraction means connected to an output of said laser for recovering a fraction of the energy of each emitted message pulse; a band-pass filter connected to said extraction means and provided with a pass band centered on said recurrence frequency; peak-detection means connected to said band-pass filter for generating a feedback signal proportional to the magnitude of the recovered energy fraction of at least some of said high-level message pulses, said peak-detection means comprising a coherent demodulator driven by a train of clock pulses of a cadence equal to said recurrent frequency; a connection extending from said peak-detection means to a control input of said pulse-forming means for stabilizing the amplitude of said high-level message pulses in response to said feedback signal; integrating circuitry connected to said extraction means in parallel with said band-pass filter for averaging the recovered energy fraction; a current generator in cascade with said integrating circuitry deriving from the averaged energy fraction a biasing signal in the form of a reference current slightly exceeding said threshold, said reference current being fed to said laser for establishing a predetermined operating point therefor; and an adder inserted between said pulse-forming means and a driving input of said laser, said adder having an input connected to said current generator for delivering a combination of said biasing signal and said message pulses to said driving input.
Claim 3
Dependent Claim
15 words
A system as defined in claim 1 wherein said band-pass filter comprises a frequency-selective amplifier.
Claim 4
Dependent Claim
68 words
A system as defined in claim 1 wherein said pulse-forming means comprises a coder controlled by said clock pulses for generating a sequence of pulse pairs each consisting of a low-level message pulse and a high-level message pulse, said clock pulses being a square wave having cycles in quadrature with said pulse pairs whereby alternate half-cycles of said square wave each coincide with half a high-level message pulse.
Claim 5
Dependent Claim
31 words
A system as defined in claim 1 or 3 wherein said extraction means comprises a photodetector and a beam splitter positioned to illuminate said photodetector with radiation emitted by said laser.
Claim 6
Dependent Claim
33 words
A system as defined in claim 4 wherein said beam splitter is a partly reflecting semitransparent mirror transmitting a major part of the emitted radiation to an optical fiber aligned with said laser.
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) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |