Self-suppression of leading-fiber-induced noise in separated OEO vibration measurement using beat frequency detection

We propose a vibration sensor based on dual-frequency optoelectronic oscillator (OEO) for self-suppression of leading-fiber-induced noise. In the two OEO loops, the acousto-optic modulator (AOM) is used as a modulator to direct the carriers and sidebands into a Michelson interferometer, significantly enhancing sensitivity. Additionally, the two OEO loops share the same leading fiber and sensing interferometer, forming a cross-reference structure through dense wavelength-division multiplexing (DWDM). Environmental disturbances are significantly reduced through beat frequency detection, and the measurement signal is further amplified. In experiments, the noise suppression ratio of the leading fiber was 41.98 dB (200 Hz to 1 kHz), with a 5.58 dB enhancement in the measurement signal. This method allows for the separation of the sensing unit and optoelectronic system while maintaining high signal-to-noise ratio (SNR), improving the system's reliability, maintainability, and convenience.