Heterodyne processing scheme for low coherence interferometric sensor systems

Author

Meggitt, B.T. ; Boyle, W.J.O. ; Grattan, K.T.V. ; Baruch, A.E. ; Palmer, A.W.

Author_Institution

Dept. of Electron. & Electr. Eng., King´´s Coll., London, UK

Volume

138

Issue

6

fYear

1991

fDate

12/1/1991 12:00:00 AM

Firstpage

393

Lastpage

395

Abstract

A heterodyne signal processing scheme is demonstrated as a `proof-of-principle´ of a technique to increase greatly the `carrier´ frequency available in low coherence interferometric sensor systems. An interferometer is formed containing a Bragg cell which acts as the local interferometer. The sensing interferometer is formed in a second remotely placed modulated Michelson interferometer which is optical-fibre-coupled to the local interferometer. The Doppler frequency shift generated in the sensing interferometer modulates the `carrier´ in a single sideband fashion. The scheme operates as a conventional heterodyne system over the coherence profile of the source. The system is fully fibre optic compatible and potentially has applications in wide modulation bandwidth sensor systems

Keywords

demodulation; fibre optic sensors; light interferometers; Bragg cell; Doppler frequency shift; coherence profile; fibre optic compatible; heterodyne signal processing scheme; local interferometer; low coherence interferometric sensor systems; modulation bandwidth sensor systems; remotely placed modulated Michelson interferometer; sensing interferometer;

fLanguage

English

Journal_Title

Optoelectronics, IEE Proceedings J

Publisher

iet

ISSN

0267-3932

Type

jour

Filename

108529