An Optical Phased Array System with a Controllable Main Lobe and Null

Null steering technique can be used to reduce the influence of electromagnetic pollution on phased array systems, which is of great importance as the phased array system usually works in an interference environment. This paper proposes a wideband optical phased array system that can control the main lobe and null independently. An optical spatial filter achieved by an optical delay network and balanced photodetectors is used after a classical optical phased array to generate and control null. In the semi-physical simulation system, the main lobe and null can be steered at least <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm \mathbf{40}^{\circ}$</tex> while the null depth is larger than 60 dB.