Application of long-period-grating sensors to respiratory plethysmography

Thomas D.P. Allsop*, Karen Carroll, Glynn D. Lloyd, David J. Webb, Martin Miller, Ian Bennion

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review


    A series of in-line curvature sensors on a garment are used to monitor the thoracic and abdominal movements of a human during respiration. These results are used to obtain volumetric tidal changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The curvature sensors are based on long-period gratings (LPGs) written in a progressive three-layered fiber to render the LPGs insensitive to the refractive index external to the fiber. A curvature sensor consists of the fiber long-period grating laid on a carbon fiber ribbon, which is then encapsulated in a low-temperature curing silicone rubber. The sensors have a spectral sensitivity to curvature, dλ/dR from ∼7-nm m to ∼9-nm m. The interrogation technique is borrowed from derivative spectroscopy and monitors the changes in the transmission spectral profile of the LPG's attenuation band due to curvature. The multiplexing of the sensors is achieved by spectrally matching a series of distributed feedback (DFB) lasers to the LPGs. The versatility of this sensing garment is confirmed by it being used on six other human subjects covering a wide range of body mass indices. Just six fully functional sensors are required to obtain a volumetric error of around 6%. © 2007 Society of Photo-Optical Instrumentation Engineers.

    Original languageEnglish
    Article number064003
    JournalJournal of Biomedical Optics
    Issue number6
    Publication statusPublished - 19 Dec 2007

    Bibliographical note

    Thomas Allsop, Karen Carroll, Glynn Lloyd, David J. Webb, Martin Miller and Ian Bennion, "Application of long-period-grating sensors to respiratory plethysmography", J. Biomed. Opt. 12, 064003 (Dec 19, 2007); doi:10.1117/1.2821198 Copyright 2007 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


    • curvature sensing
    • long-period gratings
    • respiratory monitoring


    Dive into the research topics of 'Application of long-period-grating sensors to respiratory plethysmography'. Together they form a unique fingerprint.

    Cite this