Photonic time-delay beam-forming architectures using polarization switching arrays

Photonic time delay line (PTDL) architectures have been proposed for transmit/receive mode antenna applications. These architectures are based on two dimensional pixelated optical arrays that act as optical polarization switching elements. Such elements can be nematic liquid crystal (NLC) arrays, ferroelectric liquid crystal (FLC) arrays, and magneto-optic arrays. Optical delay lines can be formed using either free space or solid optics propagation, as well as non-polarization maintaining fiber propagation for the case of long time delays. In this paper, various optical array based optical beamformer architectures are presented and compared. These different architectures are based on Thompson polarization beamsplitters, and polarizing cube beamsplitters, for both transmissive and reflective geometries. A novel ternary time delay architecture is also introduced that can give 3 ^N different time delay settings. In addition, a novel wavelength multiplexing architecture using a single channel dispersive fiber PTDL in cascade with multichannel PTDL is proposed for further hardware size and weight reduction.