Wavelength Detection of Coherence-Multiplexed Fiber-Optic Sensors Based on Long-Period Grating Pairs

Multiplexed fiber-optic sensors based on long-period grating pairs (LPGPs) are presented. With a low-coherence reflectometry, the spectral responses of the specially configured LPGP sensors are precisely quantified from the corresponding sub-reflectograms through a fast Fourier transformation (FFT). By monitoring the wavelength shift of the LPGP sensors, temperature is measured experimentally, and good performance is obtained