Integrated Thermal Silica Micro-Resonator Waveguide System With Ultra-Low Fluorescence

C. Pyrlik1, J. Schlegel1, F. Böhm2, A. Thies1, O. Krüger1, O. Benson2, A. Wicht1, and G. Tränkle1

Published in:

IEEE Photonics Technol. Lett., vol. 31, no. 6, pp. 479-482 (2019).

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Thermally grown silica is one of the most desirable materials for the realization of optical waveguides and whispering-gallery mode micro-resonators due to the ultra-low propagation loss and broad transparency window from UV to mid-IR. Here, we present the design, fabrication, and characterization of a high-Q ring-resonator device with a monolithically integrated evanescent rib waveguide coupler made solely from silica thermally grown on a Si substrate. The device delivered an intrinsic Q-factor of 3.7×106 and operated close to the critical coupling regime for both TE and TM polarizations. The achieved Q-factors were more than three orders of magnitude higher than those of comparable silica resonator devices. Furthermore, we showcase the ultra-low parasitic fluorescence unique to thermally grown silica and compare it to a device fabricated in Si3N4.

1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany
2 Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany

Index Terms:

Integrated optics, optical resonators, whispering-gallery modes.