In vibration sensing using a fiber Bragg grating (FBG) based on the intensity modulation scheme, light incident on a FBG is narrow-band light tuned to the slope in a reflectance spectrum of the FBG. Since the sensor sensitivity is proportional to the slope of the spectrum curve, enhancement of the sensitivity requires the slope to be steeper. In this paper, vibration sensing by usee of an in-fiber Fabry-Perot interferometer with FBG reflectors (FBG-FPI) is presented. Because a reflectance spectrum of a FBG-EPI has much steeper slope thatn a single FBG, a FBG-FPI yields improvement in sensitivity of the sensing. High-sensitivity measurement of vibration of a piezoelectric transducer is experimentally demonstrated. Comparing to a vibration sensor using a single FBG, the use of the FPI structure has increased the sensitivity of vibration by 30dB.

Date Published: 5 October 2009
PDF: 4 pages
Proc. SPIE 7503, 20th International Conference on Optical Fibre Sensors, 75033L (5 October 2009); doi: 10.1117/12.834166

Published in SPIE Proceedings Vol. 7503:
20th International Conference on Optical Fibre Sensors
Julian D. C. Jones, Editor(s)