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oai:gredos.usal.es:10366/1460372025-04-30T20:35:57Zcom_10366_133237com_10366_4512com_10366_3823col_10366_133238

2021-05-20T07:03:49Z urn:hdl:10366/146037 Low-loss 3D-laser-written mid-infrared LiNbO_3 depressed-index cladding waveguides for both TE and TM polarizations Nguyen, Huu-Dat Ródenas, Airan Vázquez de Aldana, Javier R. Martín, Guillermo Martínez, Javier Aguiló, Magdalena Pujol, Maria Cinta Díaz, Francesc High numerical aperture optics Laser materials processing Material properties Nonlinear optical devices Refractive index Waveguide modes We report mid-infrared LiNbO3 depressed-index microstructured cladding waveguides fabricated by three-dimensional laser writing showing low propagation losses (~1.5 dB/cm) at 3.68 µm wavelength for both the transverse electric and magnetic polarized modes, a feature previously unachieved due to the strong anisotropic properties of this type of laser microstructured waveguides and which is of fundamental importance for many photonic applications. Using a heuristic modeling-testing iteration design approach which takes into account cladding induced stress-optic index changes, the fabricated cladding microstructure provides low-loss single mode operation for the mid-IR for both orthogonal polarizations. The dependence of the localized refractive index changes within the cladding microstructure with post-fabrication thermal annealing processes was also investigated, revealing its complex dependence of the laser induced refractive index changes on laser fabrication conditions and thermal post-processing steps. The waveguide modes properties and their dependence on thermal post-processing were numerically modeled and fitted to the experimental values by systematically varying three fundamental parameters of this type of waveguides: depressed refractive index values at sub-micron laser-written tracks, track size changes, and piezo-optic induced refractive index changes. 2021-05-20T07:03:49Z 2021-05-20T07:03:49Z 2017-02 info:eu-repo/semantics/article Huu-Dat Nguyen, Airán Ródenas, Javier R. Vázquez de Aldana, Guillermo Martín, Javier Martínez, Magdalena Aguiló, Maria Cinta Pujol, and Francesc Díaz, "Low-loss 3D-laser-written mid-infrared LiNbO3 depressed-index cladding waveguides for both TE and TM polarizations," Opt. Express 25, 3722-3736 (2017) http://hdl.handle.net/10366/146037 10.1364/OE.25.003722 1094-4087 eng MAT2016-75716-C2-1-R (AEI/FEDER,UE) TEC2014-55948-R FIS2013-44174-P UIC016 SA046U16 http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional