Performance-stabilization system for an electrical component emitting pulsed energy

Claim 1

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

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.