Integrated dual-slab waveguide interferometer for glucose concentration detection in the physiological range

Meng Wang, Sanna Uusitalo, Miia Määttälä, Risto Myllylä, Markku Känsäkoski

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

2 Citations (Scopus)


This paper presents a label-free optical biosensor based on a Young's interferometer configuration that uses a vertically integrated dual-slab waveguide interferometer as sensing element. In this element, linearly polarized light is coupled into a dual-slab waveguide chip from the input end-face, and the in-coupled zeroth order mode propagates in separated upper and lower waveguides. At the output end-face, the two closely spaced coherent beams diffract out and produce an interference fringe pattern. An evanescent wave field, generated on the surface of the upper waveguide, probes changes in the refractive index of the studied sample, causing a phase shift in the fringe pattern. Compared to a conventional integrated Young's interferometer utilizing a Y-junction as the beam splitter, the dual-slab waveguide Young's interferometer has the advantage of easy fabrication and large tolerance to the input-coupling beam. This paper builds a measurement system to investigate sensor performance using glucose solutions with various concentrations. These glucose concentration measurements are performed within the physiological range of 30mg/dl ~ 500mg/dl. The results indicate that a dual-slab waveguide interferometer yields an average phase resolution of 0.002 rad, which corresponds to an effective refractive index change of 4×10-8 with an interaction path length of 15 mm.
Original languageEnglish
Title of host publicationProceedings of SPIE
Subtitle of host publicationOptical Sensors 2008
PublisherInternational Society for Optics and Photonics SPIE
ISBN (Print)978-0-8194-7201-4
Publication statusPublished - 2008
MoE publication typeA4 Article in a conference publication
EventSPIE Photonics Europe, Optical Sensors 2008 - Strasbourg, France
Duration: 7 Apr 200811 Jul 2008

Publication series

SeriesProceedings of SPIE


ConferenceSPIE Photonics Europe, Optical Sensors 2008

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