Quadrature Wavelength Scanning Interferometry

Giuseppe Moschetti, Alistair Forbes, Richard K. Leach, Xiangqian Jiang, Daniel O'Connor

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


A novel method to double the measurement range of wavelength scanning interferometery (WSI) is described. In WSI the measured optical path difference (OPD) is affected by a sign ambiguity, that is, from an interference signal it is not possible to distinguish whether the OPD is positive or negative. The sign ambiguity can be resolved by measuring an interference signal in quadrature. A method to obtain a quadrature interference signal for WSI is described, and a theoretical analysis of the advantages is reported. Simulations of the advantages of the technique and of signal errors due to nonideal quadrature are discussed. The analysis and simulation are supported by experimental measurements to show the improved performances.
Original languageEnglish
Pages (from-to)5332-5340
Number of pages9
JournalApplied Optics
Issue number20
Publication statusPublished - 6 Jul 2016


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