Accession Number : ADD018478

Title :   Optically Powered Amplifier Used by an Electromagnetic Field Sensor to Amplify an Electrical Signal from an Antenna.

Descriptive Note : Patent, Filed 13 May 94, patented 14 Feb 95,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Hilliard, Donald P

Report Date : 14 Feb 1995

Pagination or Media Count : 7

Abstract : An electromagnetic field sensing apparatus detects an incoming electromagnetic field and provides an RF electrical signal indicative of the strength of the field. The electromagnetic field sensing apparatus includes a metallic antenna which intercepts the incoming planar electromagnetic wave and provides an electrical signal indicative of the strength/intensity of the field. A microwave amplifier receives the electrical signal, amplifies the signal by a factor of at least 100 and then supplies the amplified signal to an electro-optic modulator. A first light source located along a first optical path transmits polarized laser light through the electro-optic modulator. The electro-optic modulator, in response to the amplified electrical signal modulates the polarized light when the metallic antenna detects the incident electromagnetic wave. A photodetector located along the first optical path detects the modulated light as it exists from the electro-optic modulator. In this manner incident planar wave electromagnetic fields are detected and measured. A second light source, located along a second optical path, transmits a monochromatic laser light beam along the second optical path to a photovoltaic cell which then provides a DC bias voltage to the microwave amplifier.

Descriptors :   *POWER AMPLIFIERS, *MICROWAVE AMPLIFIERS, ELECTROMAGNETIC FIELDS, METALS, OPTICS, POLARIZATION, DETECTION, DETECTORS, ELECTROOPTICS, CELLS, INTENSITY, LIGHT, PATHS, VOLTAGE, LASER BEAMS, LIGHT SOURCES, ELECTROMAGNETIC RADIATION, SIGNALS, PLANAR STRUCTURES, STRENGTH(GENERAL), ELECTRICITY, ANTENNAS, AMPLIFICATION, PHOTODETECTORS, MODULATION, BIAS, DIRECT CURRENT, RADIOFREQUENCY, PHOTOVOLTAIC EFFECT, MONOCHROMATIC LIGHT, MODULATORS, WAVES

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE