High-Quality-Factor AlGaAs-On-Sapphire Microring Resonators

Yi Zheng*, Minhao Pu, Hitesh Kumar Sahoo, Elizaveta Semenova, Kresten Yvind

*Corresponding author for this work

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Abstract

We realize an AlGaAs-on-sapphire platform through a Al<formula><tex>$_2$</tex></formula>O<formula><tex>$_3$</tex></formula>-assisted direct wafer bonding and substrate removal processes. The direct wafer bonding process is optimized concerning the intermediate layer deposition and annealing temperature to obtain a high bonding strength between the AlGaAs and sapphire wafers. High quality-factor (Q) microring resonators are fabricated using electron-beam lithography in which the charging effect is mitigated by applying an thin aluminum layer and a smooth pattern sidewall definition is obtained using a multi-pass (exposure) process. We achieve an intrinsic Q of up to <formula><tex>$\sim$</tex></formula>460,000, which is the highest Q for AlGaAs microring resonators. Taking advantage of such high Q resonators, we demonstrate an ultra-efficient nonlinear four-wave mixing process in this platform and obtain a conversion efficiency of -19.8 dB with continuous-wave pumping at a power level of 380 &#x03BC;W. We also investigate the thermal resonance shift of microring resonators with different substrate layouts and observe a superior thermal stability for devices in the AlGaAs-on-sapphire platform. The realization of the AlGaAs-on-sapphire platform also opens new prospects for AlGaAs devices in nonlinear applications in the mid-infrared wavelength range.

Original languageEnglish
JournalJournal of Lightwave Technology
Volume37
Issue number3
Pages (from-to)868 - 874
ISSN0733-8724
DOIs
Publication statusPublished - 1 Jan 2018

Keywords

  • Four-wave mixing
  • Integrated optics
  • Nonlinear optics
  • Optics resonators

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