Ultrasonic sensing using Yb3+/Er3+-codoped distributed feedback fibre grating lasers
Ye, C. C.
Tatam, R. P.
- 信息技术－已发表论文 
Yb3+/Er3+-codoped distributed feedback (YbEr-DFB) fibre grating lasers have been investigated for the detection of ultrasonic Lamb waves generated in an aluminium plate. Two sensor configurations have been investigated. A path-length-imbalanced readout Mach-Zehnder interferometer was used to measure the laser frequency shift induced by ultrasonic vibration. The resolution to out-of-plane displacement was 3 x 10(-15) m Hz(-1/2) for a continuous ultrasonic wave at a frequency of 470 kHz. Ultrasonic waves were also detected by directly monitoring the laser output power. This simplified configuration is useful for tone burst AE signals generated by a low energy impact.