High resolution and wide scale fiber Bragg grating sensor interrogation system

This paper demonstrates a high resolution and wide scale fiber Bragg grating sensor interrogation system based on fiber Fabry–Perot tunable filter (FFP-TF) and Fabry–Perot ITU filter (FPIF). By automatic control of the driving voltage of the FFP-TF, the wavelength of the laser can be tracked to the −3 dB reflectivity spectrum of the FBG. Using FPIF as the reference channel, the measurement resolution of the system is improved by wiping out the nonlinearity of the FFP-TF. A high resolution of better than 2 pm within wide strain measurement range was verified by experiments.

► High resolution and wide measurement scale.
► Automatic tracking of the FFP-TF driving voltage to −3 dB spectrum of FBG.
► Two stage auto-adapt driving voltage can provide best resolution and high speed.
► Environmental temperature can be measured before dynamic strain is applied.
► Automatic calibration of the tuning voltage versus wavelength shift.