Intensity-based LPG vibration sensor array using FBG and broadband optical source

A novel fiber optic sensor array is proposed and demonstrated by multiplexing intensity-based long-period fiber grating (LPG) sensors, in which a simultaneous multipoint detection of mechanical vibrations as well as a highly sensitive operation is realized. In the intensity-based detection scheme, multiple narrowband light sources are provided by use of a broadband amplified spontaneous emission (ASE) source and fiber Bragg gratings (FBGs) with their wavelengths adjusted to the spectral dips of the sensing LPGs. The LPG vibration sensor array is achieved by using a combination of wavelength division multiplexing (WDM) and space division multiplexing (SDM) technique. In the experiment, the LPG sensor array is constructed by multiplexing two LPG sensors in tandem and simultaneous multipoint vibration detection without crosstalk is successfully demonstrated.