Reconfigurable 2D optical tapped-delay-line to perform correlation on images

We demonstrate a reconfigurable 2D optical tapped-delay-line (OTDL) to correlate quadrature-phase-shift-keying (QPSK) 20 Gbaud data. By implementing two independent tapped-delay-lines which performs correlation over rows (inner sum), along with a coherent multiplexing of the correlated rows which performs correlation over columns (outer sum), a 2D correlator is achieved with average error vector magnitude (EVM) of ∼7.8%. Here we also search different 2×2 patterns in a 31×31 image and successfully recognize the target patterns in the image.