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arXiv · 1801.03764

Symmetric polarization insensitive directional couplers fabricated by femtosecond laser waveguide writing

Giacomo Corrielli·Simone Atzeni·Simone Piacentini·Ioannis Pitsios·Andrea Crespi·Roberto Osellame
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Abstract

We study analytically the polarization behaviour of directional couplers composed of birefringent waveguides, showing that they can induce polarization transformations that depend on the specific input-output path considered. On the basis of this study, we propose and demonstrate experimentally, by femtosecond laser writing, directional couplers that are free from this problem and also yield a polarization independent power-splitting ratio. More in detail, we devise two different approaches to realize such devices: the first one is based on local birefringence engineering, while the second one exploits ultra-low birefringence waveguides obtained by thermal annealing.

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Giacomo Corrielli, Simone Atzeni, Simone Piacentini, Ioannis Pitsios, Andrea Crespi, Roberto Osellame. 2018-01-11. Symmetric polarization insensitive directional couplers fabricated by femtosecond laser waveguide writing. https://doi.org/10.1364/oe.26.015101

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