Author, as appears in the article.: Magdalena Aguiló; Muhammad Ali Butt; Huu-Dat Nguyen; Airán Ródenas; Carolina Romero; Pablo Moreno; Javier R. Vázquez de Aldana; Rosa Maria Solé; Maria Cinta Pujol; Francesc Díaz

Department: Química Física i Inorgànica

URV's Author/s: AGUILÓ DÍAZ, MAGDALENA; Muhammad Ali Butt; Huu-Dat Nguyen; Airán Ródenas; Carolina Romero; Pablo Moreno; Javier R. Vázquez de Aldana; SOLÉ CARTAÑÀ, ROSA MARIA; PUJOL BAIGES, MARIA CINTA; DÍAZ GONZÁLEZ, FRANCISCO MANUEL

Abstract: We report on the direct low-repetition rate femtosecond pulse laser microfabrication of optical waveguides in KTP crystals and the characterization of refractive index changes after the thermal annealing of the sample, with the focus on studying the potential for direct laser fabricating Mach-Zehnder optical modulators. We have fabricated square cladding waveguides by means of stacking damage tracks, and found that the refractive index decrease is large for vertically polarized light (c-axis; TM polarized) but rather weak for horizontally polarized light (a-axis; TE polarized), this leading to good near-infrared light confinement for TM modes but poor for TE modes. However, after performing a sample thermal annealing we have found that the thermal process enables a refractive index increment of around 1.5x10−3 for TE polarized light, while maintaining the negative index change of around −1x10−2 for TM polarized light. In order to evaluate the local refractive index changes we have followed a multistep procedure: We have first characterized the waveguide cross-sections by means of Raman micro-mapping to access the lattice micro-modifications and their spatial extent. Secondly we have modeled the waveguides following the modified region sizes obtained by micro-Raman with finite element method software to obtain a best match between the experimental propagation modes and the simulated ones. Furthermore we also report the fabrication of Mach-Zehnder structures and the evaluation of propagation losses.

Research group: Física i Cristal.lografia de Materials Física i Cristal·lografia de Nanomaterials

Thematic Areas: Química Química Chemistry

licence for use: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 1094-4087

Author identifier: 0000-0001-6130-9579; ; ; ; ; ; ; 0000-0002-5769-4141; 0000-0002-1052-8031; 0000-0003-4581-4967

Record's date: 2017-05-25

Last page: 15355

Journal volume: 23

Papper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://www.osapublishing.org/oe/abstract.cfm?uri=oe-23-12-15343

Funding program: plan; Retas/FIS; FIS2013-44174-P;MAT2013-47395-C4-4-R;TEC2014-55948-R

Article's DOI: 10.1364/OE.23.015343

Entity: Universitat Rovira i Virgili

Journal publication year: 2016

First page: 15343

Publication Type: Article Artículo Article