Fiber Bragg-grating true time-delay systems: discrete-grating array 3-b delay lines and chirped-grating 6-b delay lines

Abstract

We describe wavelength-addressed 3- and 6-b fiber-optic true time-delay (TTD) lines implemented using ultraviolet-inscribed Bragg gratings. The 3-b delay line is fabricated from an array of discrete- and uniform-period Bragg gratings, and a minimum time delay of 9.09 ps is selectable, making it suitable for phased-array antenna (PAA) beamforming control at RF frequencies of up to about 3 GHz with 10/spl deg/ phase resolution. The 6-b delay line is fabricated using a chirped-period Bragg grating, and is suitable for beamforming control at RF frequencies of up to /spl sim/48 GHz, with 10/spl deg/ phase resolution.