Optical fiber loop-sensors for structural health monitoring of composites

Nguyen Q. Nguyen, Nikhil Gupta

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In the present work a fiber-optic loop-sensor is designed and tested for possible applications in structural health monitoring of composite materials. It is known that bending an optical fiber beyond a critical curvature leads to loss of optical power through the curved region. The optical power loss depends on the radius of curvature of the loop. The optical power can be measured by a photodetector and a change in the power due a change to the curvature can be measured. In the present research optical fiber-optic loop-sensors are developed that can exploit this concept. Single-mode optical fiber sensors having different loop radii, from 6-10 mm, are fabricated and calibrated for applied strain on the loop. The calibration is carried out using a 0.098 N load cell and a computer controlled translation stage having 50 nm step resolution. Results show that the sensors provide highly repeatable curves for loading and unloading cycles. Smaller loop radii lead to higher optical power losses, resulting in higher sensitivity. Calibration results show that such sensors can be used in structural health monitoring applications. In this approach the coating and cladding of optical fibers are maintained intact; therefore, the sensors are robust and can withstand several composites fabrication processes.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings - Materials and Devices for Smart Systems III
Number of pages8
StatePublished - 2009
EventMaterials and Devices for Smart Systems III - 2008 MRS Fall Meeting - Boston, MA, United States
Duration: Dec 1 2008Dec 4 2008

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


OtherMaterials and Devices for Smart Systems III - 2008 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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