True time delay generation utilizing broadband light source with fiber chirp grating array and acousto-optic beam steering and 2-D architectures
AssigneeThe United States of America as represented by the Secretary of Commerce
InventorEung G. Paek
Life of this patent
Estimating the term…
Abstract
System and method for rapidly reconfigurable two-dimensional true time delay generation for phased array antennas is described. The system utilizes a broadband light source, an array of fiber chirp gratings in a single fiber, and an acousto-optic spectrometer to generate a time-delayed linear grating. The grating is subsequently rotated to the desired angle utilizing an acousto-optic device having no moving parts.
Claims16
A 2-d true time delay generating system for phased array antennas comprising:
- an optical fiber for receiving light from a broadband light source and including an array of fiber chirp gratings defined therealong, different wavelengths of light from said light source reflected at unique locations at said fiber chirp gratings, said locations corresponding to different selected time delays;
- an acousto-optic deflector having a variable acoustic signal input for receiving light reflected at said fiber chirp gratings of said optical fiber and dispersing said reflected light at selected diffraction angles variable by an acoustic signal at said input;
- and
- an acousto-optic image rotator having no moving parts for receiving light dispersed at said acousto-optic deflector and rotating said dispersed light to a selected output angle.
An optical signal decoding device for receiving a wavelength encoded light signal and providing as an output therefrom a time delayed grating for utilization in a phased array antenna system, said device comprising:
- amplifying means for optically amplifying a wavelength encoded light signal;
- an acousto-optic deflector for receiving the amplified light signal and dispersing the light signal at selected diffraction angles to provide multiple wavelength spectra linearly arrayed at an output plane;
- and
- a window at said output plane for selection of a selected output wavelength spectrum from said multiple wavelength spectra linearly arrayed at said output plane, wherein said selection of a selected output wavelength spectrum is controlled by diffraction angle selection at said acousto-optic deflector.
A method for generating time delays for phased array antennas comprising the steps of:
- launching broadband light into an optical fiber having a plurality of selectively located fiber chirp gratings therealong to provide a wavelength encoded light signal output;
- dispersing said wavelength encoded light signal output at an output plane;
- selecting a spectrum from light disperser at said output plane corresponding to a selected one of the fiber chirp gratings at said optical fiber to thereby provide a selected time delayed linear grating;
- and
- rotating said time delayed linear grating to a desired output angle.
Dependencies are inferred from the claim text.