Instantaneous quadrature low-coherence interferometry with 3 x 3 fiber-optic couplers.


Journal Article

We describe fiber-based quadrature low-coherence interferometers that exploit the inherent phase shifts of 3 x 3 and higher-order fiber-optic couplers. We present a framework based on conservation of energy to account for the interferometric shifts in 3 x 3 interferometers, and we demonstrate that the resulting interferometers provide the entire complex interferometric signal instantaneously in homodyne and heterodyne systems. In heterodyne detection we demonstrate the capability for extraction of the magnitude and sign of Doppler shifts from the complex data. In homodyne detection we show the detection of subwavelength sample motion. N x N (N > 2) low-coherence interferometer topologies will be useful in Doppler optical coherence tomography (OCT), optical coherence microscopy, Fourier-domain OCT, optical frequency domain reflectometry, and phase-referenced interferometry.

Full Text

Duke Authors

Cited Authors

  • Choma, MA; Yang, C; Izatt, JA

Published Date

  • November 2003

Published In

Volume / Issue

  • 28 / 22

Start / End Page

  • 2162 - 2164

PubMed ID

  • 14649928

Pubmed Central ID

  • 14649928

Electronic International Standard Serial Number (EISSN)

  • 1539-4794

International Standard Serial Number (ISSN)

  • 0146-9592

Digital Object Identifier (DOI)

  • 10.1364/ol.28.002162


  • eng