Three-element fiber-type optical phased array antenna with high-speed two-dimensional optical beam steering

A fiber-type optical phased array antenna is proposed as a new configuratio n of phased array antennas operating in the optical frequency domain. The p roposed antenna consists of fibers that connect an optical beamforming netw ork consisting of integrated optical waveguides to an array antenna consist ing of microlenses as the element antenna. High-speed two-dimensional optic al beam steering can be achieved by reducing the relative phase fluctuation between element antennas and the generation of the grating lobe, In an exp eriment on the three-element fiber-type optical phased array antenna, three 1 x 2 variable power dividers and four variable phase shifters are integra ted on a LiNbO3 substrate as the optical beamforming network, and graded-in dex-fiber (GIF) lenses are used as the antenna elements. These components a re connected through polarization-maintaining seers (PMF). The 3-dB bandwid th of the integrated variable phase shifter is from de to 924 MHz, and the optical beam steering range of the three-element array is 0.2 degrees; they are arranged in a triangle. The parameters of the GIF lens are optimized a nd it is estimated that at the maximum gain coefficient a grating lobe leve l of -14.5 dB and a gain coefficient of 0.815 can be obtained. (C) 1999 Scr ipta Technica.