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Q: Fachverband Quantenoptik und Photonik

Q 23: Poster I

Q 23.32: Poster

Tuesday, March 12, 2024, 17:00–19:00, Tent B

Nonlinear characterization of in-house fabricated thin film lithium niobate waveguides — •Alexej Widajko, Laura Bollmers, Harald Herrmann, Laura Padberg, and Christine Silberhorn — Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), Warburger Str. 100, D-33098 Paderborn

Thin film lithium niobate (TFLN) is an evolving platform for photonic circuits for different application areas. In particular, the high nonlinearity and the wide transparency range of LiNbO₃ together with the tight confinement in nanophotonic waveguides enable the realization of efficient frequency converters e.g. for applications in quantum computing and quantum cryptography.

However, to exploit the full potential of nonlinear TFLN devices the fabrication process, which includes the fabrication of the optical waveguides and the periodic poling for phase-matching of the targeted nonlinear process, must be optimized.

In this work we are focussing on the development of an efficient nonlinear characterization setup for TFLN, which allows to assess the quality of the devices. We primarily use second harmonic generation (SHG) with the fundamental wave in the telecom wavelength range to study the nonlinear properties of in-house fabricated TFLN devices. We give a short overview of the fabrication process, discuss some first results on SHG characterization and initial work on photon pair generation via parametric down-conversion using the fabricated devices.

Keywords: TFLN/LNOI; SHG; quasi phase-matching; periodic poling; photon pair generation