A Simultaneous Frequency and Angle-of-Arrival Measurement System Based on Stimulated Brillouin Scattering

A simultaneous frequency and angle-of-arrival (AOA) measurement system based on stimulated Brillouin scattering (SBS) is proposed and demonstrated. This system utilizes the SBS for narrowband frequency selection and amplification of the reference chirp optical signal (COPS) modulated by a linear frequency modulation signal to capture the pulse occurrence time and amplitude in the temporal domain, which can simultaneously map the precise frequency and phase difference information of signals under test. The AOA can be obtained through the phase difference. A dual-drive Mach–Zehnder modulator single DC port is fed by two different DC biases to construct two phase-to-amplitude mapping curves. They ensure that there is no ambiguity in the measurement of AOA in a large frequency range. In the VPI simulation, the frequency measurement from 10 to 30 GHz with an accuracy of 15.39 MHz, and the phase difference measurement from −150°to 150° for unambiguous AOA measurement are demonstrated simultaneously.