Composite-embedded highly birefringent optical fiber strain gauge with zero thermal-apparent strain

David G. Luke; Roy McBride; Julian D. C. Jones; Peter A. Lloyd; James G. Burnett; Alain H. Greenaway

doi:10.1117/12.245167

19 July 1996 Composite-embedded highly birefringent optical fiber strain gauge with zero thermal-apparent strain

David G. Luke, Roy McBride, Julian D. C. Jones, Peter A. Lloyd, James G. Burnett, Alain H. Greenaway

Proceedings Volume 2861, Laser Interferometry VIII: Applications; (1996) https://doi.org/10.1117/12.245167
Event: SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 1996, Denver, CO, United States

Abstract

We demonstrate temperature-insensitive strain measurement in a carbon fiber composite panel using a sensor based on broad-band interferometry in highly-birefringent optical fiber. The sensing element forms an unbalanced Fabry-Perot cavity in the measurement arm of a tandem interferometer. This is interrogated using an LED source and a scanning Michelson interferometer, producing three distinct interferograms, two of which relate to the group delay (GD) of the eigenmodes of the sensing element, the other providing a zero-OPD reference in the scanning interferometer. We measure the GD of each interferogram by dispersive Fourier-transform spectroscopy. Changes in strain and temperature in the measurement fiber affect the group delays of the sensing interferograms, but do not affect the zero-OPD interferograms, which is therefore used as the origin for group delay measurements. We determine a linear transformation relating the measured group delays to strain and temperature. Inverting this transformation then provides a means of recovering strain and temperature from measurements of group delay. We apply this technique to the simultaneous measurement of strain and temperature in the composite panel. Typical measurement errors are 7 microsecond(s) train and 0.7 K. The measured values are independent, and the strain values show no evidence of thermal-apparent strain.

Citation Download Citation

David G. Luke, Roy McBride, Julian D. C. Jones, Peter A. Lloyd, James G. Burnett, and Alain H. Greenaway "Composite-embedded highly birefringent optical fiber strain gauge with zero thermal-apparent strain", Proc. SPIE 2861, Laser Interferometry VIII: Applications, (19 July 1996); https://doi.org/10.1117/12.245167

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available