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US 5,477,379 AGranted
Electrical pulse operated laser sampling light amplifier
AssigneeThe Research Foundation of State University of New York
InventorSheldon S. L. Chang
Life of this patent
Estimating the term…
Abstract
A sub-nanosecond pulse operated semiconductor laser amplifier which admits light input for a time interval after the commencement of the electrical pulse. The duration of the said time interval is shorter than that of the said electrical pulse. Amplified light output reaches a peak value after the termination of the said electrical pulse. The pulsed operation can be repeated a few billion times per second. Applications in a fiber-optics communication system, a bar code scanner, and in a super speed camera are described.
Claims6
A bar code scanner, which comprises:
- an enhanced light detector;
- including a semiconductor laser light amplifier having an input end and an output end and means defining a resonant cavity situated between and coupled to the input end and the output end;
- means for generating electric current pulses, the current pulse generating means being coupled to the laser light amplifier to apply electric current pulses to the light amplifier to inject minority carriers into the resonant cavity thereof;
- the electric current pulses generated by the pulse generating means being of sufficient magnitude and duration to raise the number of the minority carriers above a critical level temporarily after the application of each of the current pulses, the current pulses being sufficiently separated in time for the minority carriers to decay below the critical level after the termination of each of the current pulses, said critical level of minority carriers being defined as the minimum number of minority carriers above which an intensity of light in the resonant cavity would rise exponentially with time even without further light input;
- and
- a pulsed laser light source, the pulsed laser light source emitting pulses of laser light, which pulses are detected by the enhanced light detector, the pulsed laser light source and the enhanced light detector being operatively synchronized.
3 more elements
A super speed video camera, which comprises:
- an array of enhanced light detectors each enhanced light detector including a semiconductor laser light amplifier having an input end and an output end and means defining a resonant cavity situated between and coupled to the input end and the output end;
- means for generating electric current pulses, the current pulse generating means being coupled to the laser light amplifier to apply electric current pulses to the light amplifier to inject minority carriers into the resonant cavity thereof;
- the electric current pulses generated by the pulse generating means being of sufficient magnitude and duration to raise the number of the minority carriers above a critical level temporarily after the application of each of the current pulses, the current pulses being sufficiently separated in time for the minority carriers to decay below the critical level after the termination of each of the current pulses, said critical level of minority carriers being defined as the minimum number of minority carriers above which an intensity of light in the resonant cavity would rise exponentially with time even without further light input;
- a diode light detector situated adjacent to the output end of the pulsed laser light amplifier, the diode light detector receiving a light output emitted by the laser sampling light amplifier and converting the light output into electric current;
- and
- means for supplying electric current pulses simultaneously to each of the enhanced light detectors of the array, the array being positioned at a focal plane of said super speed video camera.
3 more elements
A communication system, which comprises:
- a plurality of pulsed laser sampling light amplifiers, the pulsed laser sampling light amplifiers including a semiconductor laser light amplifier having an input end and an output end and means defining a resonant cavity situated between and coupled to the input end and the output end;
- means for generating electric current pulses, the current pulse generating means being coupled to the laser light amplifier to apply electric current pulses to the light amplifier to inject minority carriers into the resonant cavity thereof;
- the electric current pulses generated by the pulse generating means being of sufficient magnitude and duration to raise the number of the minority carriers above a critical level temporarily after the application of each of the current pulses, the current pulses being sufficiently separated in time for the minority carriers to decay below the critical level after the termination of each of the current pulses, said critical level of minority carriers being defined as the minimum number of minority carriers above which an intensity of light in the resonant cavity would rise exponentially with time even without further light input;
- means for generating a control signal, the control signal generating means being coupled to the current pulse generating means and providing a control signal thereto for controlling the timing of the electric current pulses generated by the pulse generating means, and wherein, each of the laser sampling light amplifiers being provided with an input light signal and generating an output signal;
- and
- a controller, the controller being coupled to each of the pulsed laser sampling light amplifiers and providing a control signal thereto.
3 more elements
Dependencies are inferred from the claim text.