“The latest technological developments have led researchers to successfully propose a laser phase demodulation measurement system based on a polarization maintaining 3 × 3 fiber coupler. The system achieves phase demodulation through photoelectric conversion and differential cross multiplication, simplifying the structure and improving demodulation stability. Simulation and experimental results show that the demodulation results of the system are highly consistent with the preset values, and the phase fluctuation power spectral density is consistent, meeting the requirements of stable and reliable measurement systems, and bringing important breakthroughs to the field of laser phase measurement.”