Noise Suppression Method of Fiber Optic Sensors Driven by Broadband Light Source

Noise floor is an important metric for fiber optic sensors. In particular, common-mode noise (CMN) suppression is critical to improving the system’s ability to detect weak signals. In this letter, an innovative method for reducing noise in white-light-driven sensors is proposed. This structure fully utilizes the broad spectrum of white light and the wavelength selectivity of fiber gratings. The proposed CMN suppression method is capable of suppressing the phase noise of the light source, as well as the noise due to environmental disturbances. The experiments demonstrate that the noise floor of this vibration sensor is about -88 dB/Hz above 30Hz with 10km disturbed transmission fiber. The max 1/f noise reduction can reach approximately 60 dB near 5 Hz, while the max transmission path noise suppression exceeds 103 dB at hundreds of Hz. The proposed structure has the potential to achieve higher resolution in wavelength division multiplexing (WDM) sensor arrays without excessive cost.