Photonic angle-of-arrival measurement of microwave signals using a triangular wave

A novel, to the best of our knowledge, photonics-assisted approach for measuring the angle-of-arrival (AOA) of microwave signals with a large measurement range is pro-posed. The system utilizes a dual-drive Mach-Zehnder modulator (DDMZM) for signal modulation, followed by an optical filter for sideband selection. The dc port of the DDMZM is fed by a triangular wave to generate a pair of opposite frequency shifts. An intermediate frequency (IF) signal with a periodic phase jump is obtained after photode-tection. The AOA of the incoming signals can be estimated by measuring the value of the phase jump. The key novelty of the proposed scheme lies in the application of a triangular wave to shift the frequency of optical signals, which intro-duces a periodic phase jump to the IF signal. The system incorporates only a single optical channel, largely reducing the system complexity. Experimental results show that an AOA measurement with a range of -70.8 degrees to 70.8 degrees is realized, with errors confined to within +/- 2 degrees. (c) 2023 Optica Publishing Group