InGaAs Spectrometer and F-P Filter Combined FBG Sensing Multiplexing Technique

A novel fiber Bragg grating (FBG) sensing multiplexing system based on the combination of InGaAs spectrometer and Fabry-Perot (F-P) filter (InGaAs/F-P) is proposed. The multiplexing system only demodulates FBG sensors whose peak wavelengths are shifting. The demodulation can be sequenced according to each sensor's priority, latency time and wavelength shifting. What is more, the monitor section of that system is not influenced by environmental temperature and source intensity fluctuations. At the average signal repeat rate of 6Hz, the average delay time of the conventional wavelength- and spatial-division combined system, the long period grating (LPG) combined system and the InGaAs/F-P system are 303, 97, and 6 ms, respectively. Simulation analysis and experiment work demonstrated that the InGaAs/F-P system is more rational and smart than other counterparts.