DFB fiber laser sensor for simultaneous strain and temperature measurements in concrete structures

Oliver Hadeler; D. J. Richards; John P. Dakin

doi:10.1117/12.349744

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31 May 1999 DFB fiber laser sensor for simultaneous strain and temperature measurements in concrete structures

Oliver Hadeler, D. J. Richards, John P. Dakin

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Proceedings Volume 3670, Smart Structures and Materials 1999: Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials; (1999) https://doi.org/10.1117/12.349744
Event: 1999 Symposium on Smart Structures and Materials, 1999, Newport Beach, CA, United States

Abstract

A distributed feedback (DFB) fiber laser sensor for simultaneously measuring strain and temperature has been developed. The DFB fiber laser consists of a single fiber Bragg grating written in a low birefringent rare-earth doped fiber. By measuring the rf beat frequency between the two orthogonal polarized lasing modes and the absolute wavelength of one mode, both strain and temperature can be determined simultaneously to an accuracy of plus or minus 3 (mu) (epsilon) and plus or minus 0.04 degrees Celsius. Multiplexing capabilities make this sensor ideal for monitoring several locations within a civil engineering structure. Three gauge protection systems were developed to prevent damage to the fiber during embedment and insulate it from the high alkaline environment of the concrete. This sensor is easy to install, provides excellent strain transfer from the concrete to the optical fiber and is thin enough not to degrade the concrete structure.

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Oliver Hadeler, D. J. Richards, and John P. Dakin "DFB fiber laser sensor for simultaneous strain and temperature measurements in concrete structures", Proc. SPIE 3670, Smart Structures and Materials 1999: Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials, (31 May 1999); https://doi.org/10.1117/12.349744

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