Broadband tunable channelized microwave instantaneous multi-frequency measurement based on interleaved double-optical frequency comb

A broadband tunable channelized microwave instantaneous multi-frequency measurement system based on interleaving dual-optical frequency combs (OFC) is proposed. In the first branch, the unknown signals are input into a dual-parallel Mach–Zehnder modulator for carrier-suppressed single-sideband modulation. In the second branch, the frequency-shifted signal which is related to the reference signal is input into the OFC generator. The generated 25-line OFC is split into two paths. One path is frequency-shifted so that the two OFCs are interleaved distribution. The two OFCs are input into the photonic I/Q receivers to mix with the unknown signals for intermediate frequency reception. By adjusting the reference signal frequency f0≥24.5Δf, a measurement range of f0−24.5Δf to f0+25.5Δf GHz can be achieved. Simulation experiments demonstrate that the system can measure frequencies in the range of 0 to 70 GHz, with a measurement error of <8 MHz. Moreover, the system achieves an image rejection ratio of >14 dB, with passband power fluctuation less than 0.2 dB.