High stability multiplexed fibre interferometer and its application on absolute displacement measurement and on-line surface metrology

Dejiao Lin, Xiangqian Jiang, Fang Xie, Wei Zhang, Zhang Lin, Ian Bennion

Research output: Contribution to journalArticle

61 Citations (Scopus)


We propose a self-reference multiplexed fibre interferometer (MFI) by using a tunable laser and fibre Bragg grating (FBG). The optical measurement system multiplexes two Michelson fibre interferometers with shared optical path in the main part of optical system. One fibre optic interferometer is used as a reference interferometer to monitor and control the high accuracy of the measurement system under environmental perturbations. The other is used as a measurement interferometer to obtain information from the target. An active phase tracking homodyne (APTH) technique is applied for signal processing to achieve high resolution. MFI can be utilised for high precision absolute displacement measurement with different combination of wavelengths from the tuneable laser. By means of Wavelength-Division-Multiplexing (WDM) technique, MFI is also capable of realising on-line surface measurement, in which traditional stylus scanning is replaced by spatial light-wave scanning so as to greatly improve the measurement speed and robustness.

Original languageEnglish
Pages (from-to)5729-5734
Number of pages6
JournalOptics Express
Issue number23
Publication statusPublished - 15 Nov 2004


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