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Some theory of a dual-polarization interferometer for sensor applications

Abram, RA; Brand, S

Some theory of a dual-polarization interferometer for sensor applications Thumbnail


S Brand


It is shown that by making straightforward approximations it is possible to simplify the analysis of the measurements of a well-established dual-waveguide interferometer for sensor applications. In particular we derive approximate algebraic formulae for the mode phase shifts that are measured in the interferometric sensor when a layer of the entity to be detected is deposited. Knowledge of the shifts of both the TE and TM mode phases allows the deduction of both the thickness and refractive index of a homogeneous deposited layer, and the formulae derived make that possible with significantly reduced numerical computation. More generally the algebraic formulae and the ease with which numerical results can be obtained for a wide range of layer parameter combinations provide opportunities to improve our understanding of device behaviour. In an application of the theory to a specific practical structure, the numerical results show that the ratio of the TE and TM mode phase shifts varies linearly with deposited layer refractive index but is only weakly dependent on layer thickness, as has been observed previously in some experiments. The numerical results are interpreted using the theory and a simple formula describing the linear dependence of phase shift ratio on deposited layer refractive index is derived.


Abram, R., & Brand, S. (2015). Some theory of a dual-polarization interferometer for sensor applications. Journal of Physics D: Applied Physics, 48(12), Article 125101.

Journal Article Type Article
Acceptance Date Jan 29, 2015
Publication Date Apr 1, 2015
Deposit Date Aug 11, 2015
Publicly Available Date Mar 5, 2016
Journal Journal of Physics D: Applied Physics
Print ISSN 0022-3727
Electronic ISSN 1361-6463
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 48
Issue 12
Article Number 125101


Accepted Journal Article (212 Kb)

Copyright Statement
This is an author-created, un-copyedited version of an article published in Journal of Physics D: Applied Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/0022-3727/48/12/125101

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