Photonic-Enabled Doppler Frequency Shift Measurement for Weak Echo Signals Based on Optical Single-Sideband Mixing Using a Fixed Low-Frequency Reference

A simplified photonic-enabled Doppler frequency shift (DFS) measurement approach is proposed based on a single dual-polarization binary phase-shift keying (DP-BPSK) modulator with the help of a fixed low-frequency reference. The low-frequency reference and the transmitted signal are combined and then single-sideband mixed in the upper dual-drive Mach–Zehnder modulator (DD-MZM) in the DP-BPSK modul...