Optically triggered bulk device Gunn oscillator
First Claim
1. A microwave/millimeter wave signal generator comprising:
- a Gunn effect device comprised of material having an electrical resistivity greater than 1×
107 ohm/cm and including a pair of ohmic contacts formed on the terminal ends thereof with the distance between said contacts defining a gap having a gap length of at least 0.5 millimeters;
means for applying a relatively high bias potential across said device for generating an electrical field thereacross which is substantially beyond the oscillation threshold of said device but wherein oscillations are inhibited in absence of optical energy impinging thereon due to the extremely high resistivity of the material of said device;
an optical source for periodically illuminating said device whereupon carriers are generated across said gap causing a reduction of the resistivity of the device which is accompanied by a decrease of the electrical field across the device to the oscillation threshold level, whereupon relatively high power RF oscillations appear across said ohmic contacts and whose frequency is determined by the recombination time of the carriers generated in said material by said optical source; and
means coupled across said ohmic contacts for sensing said RF oscillations.
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Accused Products
Abstract
A high power solid state source of microwave and millimeter wave signals is provided by an optically triggered body of bulk semiconductor material selected from the Group III-V compounds including GaAs, Cr:GaAs, and Fe:InP and having a relatively long gap length which is in the order of 0.5 to 10.0 mm as well as having a resistivity which is greater than 1×107 ohm-cm. The device is further dc biased to a field of between 15 kV/cm and 35 kV/cm. Under such conditions, a very low dc current flows without any oscillatory behavior; however, illumination of the semiconductor body with a fast rising optical pulse having a wavelength suitable for carrier generation causes electrons to be lifted to the conduction band which is accompanied by a rapid reduction of the resistivity. At the same time, the electric field across the gap length decreases to a value just above the oscillation threshold whereupon high power RF oscillations are generated whose frequency is a function of the recombination time of the excited carriers.
24 Citations
12 Claims
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1. A microwave/millimeter wave signal generator comprising:
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a Gunn effect device comprised of material having an electrical resistivity greater than 1×
107 ohm/cm and including a pair of ohmic contacts formed on the terminal ends thereof with the distance between said contacts defining a gap having a gap length of at least 0.5 millimeters;means for applying a relatively high bias potential across said device for generating an electrical field thereacross which is substantially beyond the oscillation threshold of said device but wherein oscillations are inhibited in absence of optical energy impinging thereon due to the extremely high resistivity of the material of said device; an optical source for periodically illuminating said device whereupon carriers are generated across said gap causing a reduction of the resistivity of the device which is accompanied by a decrease of the electrical field across the device to the oscillation threshold level, whereupon relatively high power RF oscillations appear across said ohmic contacts and whose frequency is determined by the recombination time of the carriers generated in said material by said optical source; and means coupled across said ohmic contacts for sensing said RF oscillations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification