SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 60: Photonics IV

Q 60.5: Talk

Friday, March 10, 2023, 12:00–12:15, A320

Spectral tailoring of quasi-phase-matched nonlinear processes in Ti:LiNbO₃ waveguides using microheaters — •Jonas Babai-Hemati, Felix vom Bruch, Harald Herrmann, and Christine Silberhorn — Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), Warburger Str. 100, 33098 Paderborn, Germany

Nonlinear optical conversion processes, such as second harmonic generation (SHG) or parametric down-conversion are at the heart of many quantum optic applications. Various efficient devices have been demonstrated using periodically poled Ti-indiffused waveguides in LiNbO₃ (PPLN). Their performance, however, is often limited by inhomogeneities induced by an imperfect fabrication. We demonstrate that this problem can be mitigated by counteracting the inhomogeneities by a distinct temperature profile along the waveguide. Here, we theoretically and experimentally investigate a cascade of microheaters, inducing specifically tailored temperature profiles to improve the performance of an SHG-process. With an optimized temperature profile, we could modify the phase-matching resulting from nonuniform domain inversion or varying waveguide cross-section towards ideal spectra. Furthermore, our method also opens new possibilities to tailor spectra of nonlinear optical processes, allowing for highly efficient and tuneable generation of single photons.