Electron gun modulated by optoelectronic switching
AssigneeThomson Tubes Electroniques
InventorHenri Desmur
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Abstract
An electron gun is modulated by an optoelectronic switching device. This switching device comprises a modulated light source and at least one GaAs or Si solid-state optoelectronic switch, this switch being non-conductive when not illuminated and conductive when illuminated by the modulated light source; the device also includes components to transmit the light from the source to the switch(es). In one embodiment, the modulated light source is a laser and in a second embodiment the source is a continuous source externally modulated by a mechanical or electrooptical device. The optoelectronic switching device is connected between a high-voltage source and the cathode of an electron gun, thus modulating the cathode. The invention is particularly applicable to microwave electron tubes.
Claims15
A microwave tube electron gun comprising a means for supplying high voltage (SHT);
- a cathode (22);
- an optoelectronic switch (13) connected between said supply means and said cathode;
- and means operatively coupled to and for optically activating said optoelectronic switch (4, 5) with modulated light, said optoelectronic switch having a switching speed faster than a microsecond;
- whereby said cathode generates a modulated electron beam which is modulated in accordance with voltage modulation provided by said optoelectronic switch supplied to said cathode, said voltage modulation provided by said optoelectronic switch being responsive to the modulated light from said optically activating means.
A microwave tube electron gun comprising cathode means for generating an electron beam;
- an optoelectronic modulation means comprising in series a voltage source, an optoactive switch having alternative conductive and insulating states and an output;
- said optoelectronic modulating means further comprising a series connection of a light source of predetermined frequency to control said optoactive switch;
- means for modulating said light from said source, means for permitting transmission of said modulated light to said optoactive switch;
- and means for coupling said output of said optoelectronic modulation means to said cathode for modulating said electron beam.
An electron gun generating a modulated electron beam at a predetermined frequency comprising, a cathode for emitting electrons of the beam toward an electrode;
- an energy source for generating an electric field in a space including the cathode and the electrode in order to extract the electrons from the cathode, said energy source being coupled to the cathode through an optoelectronic switch having alternate conductive and insulating states;
- means for modulating the electron beam comprising at least a modulated light source operated at the predetermined frequency for modulating said optoelectronic switch, said modulated light source being connected to said optoelectronic switch so that, in response to the modulation imparted on the optoelectronic switch, optoelectronically switching between the conductive and insulating states, and thus the electric field in the space is correspondingly modulated to effect the modulated electron beam.
Dependencies are inferred from the claim text.