Unambiguous measurement of AOA using a DDMZM

Abstract

We propose a photonic approach for measuring the angle-of-arrival (AOA) with a large measurement range using a dual-drive Mach–Zehnder modulator (DDMZM). The echo signals received by two antennas are driven into the DDMZM. By measuring the power of output RF signal, the phase difference of two echo signals can be acquired. Moreover, the DC port of the DDMZM is fed by a two-level electrical signal to construct two mapping curves, which extends the AOA measurement range. The unambiguous AOA measurement with a range of −70.81° to 70.81° and errors of no more than ±2° is implemented. The key novelty of our scheme is that two mapping curves are acquired by a two-level electrical signal and only one channel is established. Thus, the two channels previously established by optical multiplexing elements to generate two mapping curves are no longer needed.