Barium titanate (BaTiO3) RF characterization for application in electro-optic modulators

[EN] Barium titanate (BaTiO3 or BTO) is currently one of the most promising ferroelectric materials for enabling Pockels modulation that is compatible with silicon photonic circuits. The relative permittivity of BTO has been characterized in thin films deposited on a silicon-on-insulator (SOI) substrate. High values between 800 and 1600 have been estimated at 20 GHz. Furthermore, no substantial difference has been obtained by using BTO grown by molecular beam epitaxy and sputtering. The obtained permittivity has been used to properly design the RF electrodes for high-speed modulation in hybrid BTO/Si devices. Electrodes have been fabricated and the possibility of achieving modulation bandwidths up to 40 GHz has been demonstrated. The bandwidth is limited by the microwave propagation losses and, in this case, different losses have been measured depending on the BTO growth process.Financial support from European Commission under project FP7-ICT-2013-11-619456 SITOGA, and from TEC2016-76849-C2-2-R and NANOMET Conselleria de Educació, Cultura i Esport -PROMETEOII/2014 034 are acknowledged. Álvaro Rosa also acknowledges the Spanish Ministry of Economy and Competitiveness for funding his grant.Rosa Escutia, Á.; Tulli, D.; Castera-Molada, P.; Gutiérrez Campo, AM.; Griol Barres, A.; Baquero Escudero, M.; Vilquin, B.... (2017). Barium titanate (BaTiO3) RF characterization for application in electro-optic modulators. Optical Materials Express. 7(12):4328-4336. https://doi.org/10.1364/OME.7.00432843284336712Hennings, D. (1987). Barium titanate based ceramic materials for dielectric use. International Journal of High Technology Ceramics, 3(2), 91-111. doi:10.1016/0267-3762(87)90031-2Sengupta, L., & Sengupta, S. (1997). 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