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TitleComparative study of quantitative phase imaging techniques for refractometry of optical waveguides.
Publication TypeJournal Article
Year of Publication2018
AuthorsBélanger, Erik, Jean-Philippe Bérubé, Bertrand de Dorlodot, Pierre Marquet, and Réal Vallée
JournalOpt Express
Date Published2018 Jun 25

A comparative study of quantitative phase imaging techniques for refractometry of optical waveguides is presented. Three techniques were examined: a method based on the transport-of-intensity equation, quadri-wave lateral shearing interferometry and digital holographic microscopy. The refractive index profile of a SMF-28 optical fiber was thoroughly characterized and served as a gold standard to assess the accuracy and precision of the phase imaging methods. Optical waveguides were inscribed in an Eagle2000 glass chip using a femtosecond laser and used to evaluate the sensitivity limit of these phase imaging approaches. It is shown that all three techniques provide accurate, repeatable and sensitive refractive index measurements. Using these phase imaging methods, we report a comprehensive map of the photosensitivity to femtosecond pulses of Eagle2000 glass. Finally, the reported data suggests that the phase imaging techniques are suited to be used as precise and non-destructive refractive index shift measuring tools to study and control the inscription process of optical waveguides.

Alternate JournalOpt Express
PubMed ID30119561