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arXiv · 1803.10577

Quasi-phase-matched nonlinear optical frequency conversion in on-chip whispering galleries

Richard Wolf·Yuechen Jia·Sebastian Bonaus·Christoph S. Werner·Simon J. Herr·Ingo Breunig·Karsten Buse·Hans Zappe
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Abstract

Chip-integrated whispering-gallery resonators enable compact and wavelength-agile nonlinear optical frequency synthesizers. So far, the most flexible phase-matching technique, i.e. quasi phase matching, has not been applied in this configuration. The reason is the lack of suitable thin films with alternating crystal structure on a low-refractive-index substrate. Here, we demonstrate an innovative method of realizing thin film substrates suitable for quasi phase matching by field-assisted domain engineering of lithium niobate, and subsequent direct bonding and polishing. We are able to fabricate high-Q on-chip WGRs with these substrates by using standard semiconductor manufacturing techniques. The Q-factors of the resonators are up to one million, which allows us to demonstrate quasi-phase-matched second-harmonic generation in on-chip WGRs for the first time. The normalized conversion efficiency is $9\times 10^{-4}\,\textrm{mW}^{-1}$. This method can also be transferred to other material systems.

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Richard Wolf, Yuechen Jia, Sebastian Bonaus, Christoph S. Werner, Simon J. Herr, Ingo Breunig, Karsten Buse, Hans Zappe. 2018-03-28. Quasi-phase-matched nonlinear optical frequency conversion in on-chip whispering galleries. https://arxiv.org/abs/1803.10577

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