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):

Report Date:

1995-02-14

Pagination or Media Count:

7.0

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 strengthintensity 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.

Subject Categories:

  • Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE