A Code Division Design Strategy for Multiplexing Fiber Bragg Grating Sensing Networks

Abstract

In this paper, an encoding strategy is used to design specialized fiber Bragg grating (FBG) sensors. The encoding of each sensor requires two binary codewords to define the amplitude and phase patterns of each sensor. The combined pattern (amplitude and phase) makes each sensor unique and therefore two or more sensors can be identified under spectral overlapping. In this way, we add another dimension to the multiplexing of FBG sensors, obtaining an increase factor ‘n’ to enhance the number of sensors that the system can handle. A proof-of-concept scenario with three sensors was performed, including the manufacturing of the encoded sensors. Furthermore, an interrogation setup to detect the sensors central wavelength was proposed and its working principle was theoretically developed. Results show that total identification of the central wavelength is performed under spectral overlapping between the manufactured sensors, achieving a three-time improvement of the system capacity. Finally, the error due to overlapping between the sensors was assessed obtaining approximately 3 pm, which makes the approach suitable for use in real measurement systems.

A Fiber Bragg Grating Interrogation System with Self-Adaption Threshold Peak Detection Algorithm

“…In addition, the static interrogation precision could reach 0.5 pm in the temperature experiment. In this paper, the typical interrogators based on M-Z interferometer [ 5 ], WDM+FDM [ 6 ] and the latest approaches based on encoding strategy [ 11 ], MEMS [ 24 ], on-chip AWG [ 26 ] are taken into comparison. To assess the performance, the precision, maximum capacity, interrogation and cost of different systems were compared and analyzed.…”

“…In this study, as many as 275 FBG sensors were interrogated, although the final precision was only . Triana designed an interrogation system for multiplexing FBG networks based on the encoding strategy [ 11 ]. They provided a new solution for the application of FBG networks in real measurement systems, for which the capacity was approximately three times that of the traditional WDM approach with the precision of 3 pm.…”

Algorithm of FBG Spectrum Distortion Correction for Optical Spectra Analyzers with CCD Elements

“…The multiplexing technologies and microwave-photon interrogation methods of spectrally-encoded and addressed Bragg gratings have been developed; they allow separating, spectrally, the responses of sensors in the same frequency range [ 9 , 10 , 11 , 12 ]. Some researchers worked on sensor detection and tracking using Slepyan codes [ 13 , 14 , 15 , 16 ]; thus, a measurement of temperature and deformation in the case of sensors spectra overlapping became possible. Recently, a more convenient technology, based on addressable fiber Bragg structures, was proposed [ 17 ].…”

Algorithm of FBG Spectrum Distortion Correction for Optical Spectra Analyzers with CCD Elements

“…The multiplexing technologies and microwave-photon interrogation methods of spectrally-encoded and address Bragg gratings have been developed, it allows separating spectrally the responses of sensors in the same frequency range [9,10,11,12]. Some researchers worked on sensor detection and tracking using Slepyan codes [13,14,15,16], thus a measurement of temperature and deformation in case of sensors spectra overlapping became possible. Recently, a more convenient technology, based on addressable fiber Bragg structures, was proposed [17].…”