In-Ground Optical Fibre Bragg Grating Pressure Switch for Security Applications

Gary Allwood, Graham Wild, Steven Hinckley

Research output: Chapter in Book/Conference paperConference paperpeer-review

1 Citation (Scopus)


In this study, a fibre Bragg grating (FBG) was embedded beneath three common flooring materials acting as a pressure switch for in-ground intrusion detection. This is achieved using an intensiometric detection system, where a laser diode and FBG were optically mismatched so that there was a static dc offset from the transmitted and reflected optical power signals. As pressure was applied, in the form of a footstep, a strain induced wavelength shift occurred that could then be detected by converting the wavelength shift into an intensity change. The change in intensity caused a significant change in the DC offset which behaved as on optical switch. This switch could easily be configured to trigger an alarm if required. The intention is to use the FBG sensor as an in-ground intrusion detection pressure switch to detect an intruder walking within range of the sensor. This type of intrusion detection system can be applied to both external (in soil, etc) and internal (within the foundations or flooring of the home) security systems. The results show that a person's footstep can clearly be detected through solid wood flooring, laminate flooring, and ceramic floor tiles.

Original languageEnglish
Title of host publicationThird Asia Pacific Optical Sensors Conference
EditorsJohn Canning, Gangding Peng
Place of PublicationAustralia
Number of pages6
ISBN (Print)9780819490278
Publication statusPublished - 2012
Externally publishedYes
Event3rd Asia Pacific Optical Sensors Conference (APOS) - Sydney, Australia
Duration: 31 Jan 20123 Feb 2012

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


Conference3rd Asia Pacific Optical Sensors Conference (APOS)


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