Temperature-controlled fiber Bragg grating dynamic strain detection system

A fiber Bragg grating (FBG) measurement system for dynamic strain detection has been developed. It exploits a temperature-controlled FBG as a small-band filter to measure the strain-induced wavelength shift of structurally integrated FBG sensors. This interrogation method realizes an optimal dynamic performance of the sensor also under the influence of environmental temperature changes. This has been confirmed relative to a conventional reference sensor under simulated in situ conditions in a laboratory test. The FBG system can be applied for nondestructive vibration testing of geotechnical structures, e.g. bridges and borepiles.