Modified J1....J4 method for linear readout of dynamic phase changes in a fibre-optic interferometer

Jin Wei, Ming Zhang Li, Deepak Uttamchandani, Brian Culshaw

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

2 Citations (Scopus)


Fibre optic interferometers have been extensively studied for sensing applications because of the very high sensitivities with which many physical parameters can be measured using these devices. A limiting feature of fibre interferometers is the random phase changes which occur at the interferometer output because of general environmental fluctuations, for example, due to changes of ambient temperature. These fluctuations can be compensated by active phase tracking techniques which keep the interferometer biased at quadrature. Passive demodulation techniques are of greater practical interest and the J1....J4 technique has been recently proposed as a method for the linear measurement of dynamic phase changes in a fibre interferometer. In this technique the interferometer requires no phase bias. The measurement is unaffected by random phase fluctuations in the interferometer. However, the J1....J4 technique is limited by the fact that only the magnitude of the J1....J4 Bessel components can be measured on a spectrum analyser so that no information about the sign of the Bessel function is available thereby generating some ambiguity in the read-out. In this paper, a modified technique which overcomes this limitation is demonstrated.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsRalf T. Kersten
PublisherPubl by Int Soc for Optical Engineering
Number of pages5
ISBN (Print)0819403148
Publication statusPublished - Mar 1990
Externally publishedYes
EventFiber Optic Sensors IV - Hague, Neth
Duration: 13 Mar 199014 Mar 1990

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceFiber Optic Sensors IV
CityHague, Neth

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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