Photonic integrated circuit (PIC) radio frequency I/Q signal correlator

A photonic radio frequency (RF) In-phase (I) Quadrature-phase (Q) signal correlator comprising:

• a photonic integrated circuit (PIC) comprising:
• a first optical waveguide configured to receive a laser light signal from a continuous wave (CW) laser source modulated with a first radio frequency signal to form a first RF modulated optical signal S1(t), wherein t is time;
• a first 1 to M optical splitter having an input coupled to the first optical waveguide and M outputs, the first 1 to M optical splitter configured to receive Si(t) at the input and divide the signal S1(t) to provide a signal S1′(t) at the M outputs to form M first RF modulated optical signals S1′(t), wherein each of the M first RF modulated optical signal signals S1′(t) have substantially equal power, wherein M is a positive integer greater than 1.
• M discrete optical delay lines coupled to the M outputs of the first 1−to-M optical splitter, wherein the M discrete optical delay lines each provide a separate delay from 0×Δτ to (M−1) Δ96 respectively to provide M different delayed first RF modulated optical signals S1′(t), S1′(t−-Δτ), . . . S1′(t−(M−1) Δτ), where 1/Δτ is more than twice a bandwidth of the first RF signal;
• a second optical waveguide configured to receive a laser light signal of the CW laser source modulated with a second radio frequency signal to form a second RF modulated optical signal S2(t);
• a second 1-to-M optical splitter having an input coupled to the second optical waveguide and M outputs, the second 1to M optical splitter configured to receive the modulated optical signal S2(t) at the input and divide the signal S2(t) to provide a signal S2′(t) at the M outputs to form M second RF modulated optical signals, wherein each of the M second RF modulated optical signal signals S2′(t) have substantially equal power;
• M I/Q photo receivers, wherein each I/Q photo receiver is configured to receive a different delayed first RF modulated optical signal S1′(M−1) Δτ) and a second RF modulated optical signal S2′(t) and output an in-phase (I) integrated correlated weight coefficient χreal(m) and a quadrature-phase (Q) integrated correlated weight coefficient χimag(m);
• a processor electrically coupled to the first and second outputs of the M I/Q photo receivers, the processor configured to receive and sum the χreal(m) and χimag(m) according to the summation
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• to output a frequency domain correlated signal of the first RF signal and the second RF signal having real and imaginary parts.