High speed, high performance, portable, dual-channel, optical fiber Bragg grating (FBG) demodulator

Abstract

A high speed, high performance, portable, dual-channel, optical Fiber Bragg Grating demodulator based on fiber FabryPérot tunable filter (FFP-FT) is reported in this paper. The high speed demodulation can be achieved to detect the dynamical loads of vehicles with speed of 15 mph. However, the drifts of piezoelectric transducer (PZT) in the cavity of FFP-FT dramatically degrade the stability of system. Two schemes are implemented to improve the stability of system. Firstly, a temperature control system is installed to effectively remove the thermal drifts of PZT. Secondly, a scheme of changing the bias voltage of FFP-FT to restrain non-thermal drifts has been realized at lab and will be further developed to an automatic control system based on microcontroller. Although this demodulator is originally used in Weight-InMotion (WIM) sensing system, it can be extended into other aspects and the schemes presented in this paper will be useful in many applications.

Monitoring the hysteresis effects in the strain-stress curve of carbon fiber reinforced laminates by FBG technology

“…Therefore, a FBG sensor can be used as a non-destructive sensor to detect the cracks and fatigue in materials by detecting the change of the area of hysteresis loops. Moreover, if in this experiment the optical spectral analyzer is replaced by a high speed demodulator [8], this system can be used to monitor health of materials in real time. By detecting the dissipative energy density, we can even detect and predict the fatigue of materials.…”