Journal article · Ahead of Print article
High-Quality-Factor AlGaAs-On-Sapphire Microring Resonators
Department of Photonics Engineering, Technical University of Denmark1
Nanophotonic Devices, Department of Photonics Engineering, Technical University of Denmark2
Diode Lasers and LED Systems, Department of Photonics Engineering, Technical University of Denmark3
Centre of Excellence for Silicon Photonics for Optical Communications, Centers, Technical University of Denmark4
We realize an AlGaAs-on-sapphire platform through a Al$_2$O$_3$-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 $\sim$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 μW. 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.
Language: | English |
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Publisher: | IEEE |
Year: | 2018 |
Pages: | 868-874 |
ISSN: | 15582213 and 07338724 |
Types: | Journal article and Ahead of Print article |
DOI: | 10.1109/JLT.2018.2882305 |
ORCIDs: | Pu, Minhao , Sahoo, Hitesh Kumar , Semenova, Elizaveta , Yvind, Kresten and 0000-0003-0163-9255 |