A technology is described for a Photonic Integrated Circuit (PIC) radio frequency (RF) in-phase quadrature phase (I/Q) correlator. The PIC RF Correlator can comprise two optical waveguides to receive first and second optical signals that are modulated by first and second RF signals, respectively. Two 1 to M optical splitters can split the first and second RF modulated optical signals. Optical delay lines can delay the M split first RF modulated optical signals. M optical balanced couplers can receive and combine the M first delayed RF modulated optical signals with the M split second RF modulated optical signals. Balanced photodetectors can output a differential integration on the first and second combined RF modulated optical signals for in-phase and quadrature phase signals. A processor can add the outputs of the M optical balanced photodetectors to form a frequency domain correlated signal of the first and second RF signals with real and imaginary parts.