Phase-coded Brillouin Optical Correlation Domain Analysis based on Amplitude Modulation

A phase-coded Brillouin optical correlation domain analysis (BOCDA) based on amplitude modulation was proposed. Unlike the conventional phase-coded BOCDA which suffers from non-rectangular phase transitions, the proposed phase coding based on amplitude modulation can realize perfect phase switches between 0 and π with zero-width edges. Numerical simulations and experimental results prove that it can effectively suppress the Brillouin amplification in the off-peak positions. In experiment, a 2-mm spatial resolution sensing is realized using only a 20- GHz bandwidth amplitude modulator.