Simultaneous Frequency and AOA Detection via Dual-Polarization Photonic Time Stretch

This Letter proposes a novel photonic approach for simultaneous angle-of-arrival (AOA) and frequency measurement based on time stretch. The system employs a dual-polarization single-sideband modulation structure implemented via a DP-BPSK modulator to effectively suppress dispersion-induced fading and enable orthogonal polarization multiplexing. A programmable optical filter is used to ensure spectral uniformity and prevent temporal overlap. After polarization beam splitting and photodetection, stretched waveforms are digitized using low-speed ADCs to extract both AOA and frequency. Experiments for simultaneous measurement of frequency and AOA are demonstrated, within a frequency range of 3–30 GHz and an AOA range of ±70.8°, confirming the system's capability for wideband RF sensing with relaxed electronic bandwidth requirements.