Integrated 6-bit photonic true-time-delay unit for lightweight 3-6 GHz radar beamformer

The authors have developed a low-loss integrated 6-bit photonic time-delay unit to be used in the demonstration of a photonic beamformer for eight subarrays of a 3-6 GHz phased array radar. The current architecture for the electronic true-time-delay beamformer, and the proposed architecture for the equivalent photonic true-time-delay beamformer are presented. The 6-bit photonic time-delay unit design, showing the four 4*4 crossbar switch arrays realized using two 3-in LiNbO/sub 3/ substrates, is outlined. The time-delay unit fabrication is discussed. The results of the insertion loss and crosstalk measurements for each of sixty-four paths through the photonic time-delay unit are presented.>