Mathematical modeling of intensity-modulated bent-tip optical fiber displacement sensors

Pinyo Puangmali, Kaspar Althoefer, Lakmal D. Seneviratne

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Intensity-modulated optical fiber displacement sensors have a potential to be used in a number of applications, including those in industry, military, aerospace, and medicine. Compared with other types of optical fiber sensors, intensity-modulated sensors offer distinctive advantages in that they are usually less complex, inexpensive, and less sensitive to thermal-induced strain. They are able to perform accurate contactless sensing while being of a small size and having a wide dynamic range. A common form of the intensity-modulated optical fiber sensor performs its measurement by making use of a pair of straight parallel optical fibers integrated with a moving reflector modulating the reflected optical signal intensity. Although such an optical modulation configuration exhibits good sensing ability, improvement on its performance could still be made to widen the extent of its application areas. This leads to the development of more effective intensity modulation mechanisms utilizing bent-tip optical fibers and a reflector that can either laterally slide or longitudinally move with reference to the central axis of the fibers. This paper describes such alternative sensing structures and demonstrates the derivations of mathematical models proposed for analyzing their sensing characteristics. Based on experimental studies, the models are verified and validated for the analysis of sensitivity and linearity.

Original languageBritish English
Article number5229170
Pages (from-to)283-291
Number of pages9
JournalIEEE Transactions on Instrumentation and Measurement
Issue number2
StatePublished - Feb 2010


  • Displacement sensor
  • Intensity-modulated sensor
  • Optical fiber sensor
  • Optical fiber transducer
  • Reflective intensity modulation


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