Bidirectional interconversion of microwave and light with thin-film lithium niobate

Abstract Superconducting cavity electro-optics presents a promising route to coherently convert microwave and optical photons and distribute quantum entanglement between superconducting circuits over long-distance. Strong Pockels nonlinearity and high-performance optical cavity are the prerequisites for high conversion efficiency. Thin-film lithium niobate (TFLN) offers these desired characteristics. Despite significant recent progresses, only unidirectional conversion with efficiencies orders of magnitude lower than expected has been realized. In this article, we demonstrate the first bidirectional electro-optic conversion in TFLN-superconductor hybrid system, with conversion efficiency improved by more than three orders of magnitude. Our new air-clad device architecture boosts the sustainable intracavity pump power at cryogenic temperatures by suppressing the prominent photorefractive effect that limits cryogenic performance of TFLN, and reaches an efficiency of 1.02% (internal efficiency of 15.2%). This work firmly establishes the TFLN-superconductor hybrid EO system as a highly competitive transduction platform for future quantum network applications.

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Bidirectional interconversion of microwave and light with thin-film lithium niobate

Nature Communications ◽

10.1038/s41467-021-24809-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yuntao Xu ◽

Ayed Al Sayem ◽

Linran Fan ◽

Chang-Ling Zou ◽

Sihao Wang ◽

...

Keyword(s):

Thin Film ◽

Lithium Niobate ◽

Conversion Efficiency ◽

High Performance ◽

Photorefractive Effect ◽

Optical Cavity ◽

Long Distance ◽

Superconducting Circuits ◽

Network Applications ◽

Electro Optic

AbstractSuperconducting cavity electro-optics presents a promising route to coherently convert microwave and optical photons and distribute quantum entanglement between superconducting circuits over long-distance. Strong Pockels nonlinearity and high-performance optical cavity are the prerequisites for high conversion efficiency. Thin-film lithium niobate (TFLN) offers these desired characteristics. Despite significant recent progresses, only unidirectional conversion with efficiencies on the order of 10−5 has been realized. In this article, we demonstrate the bidirectional electro-optic conversion in TFLN-superconductor hybrid system, with conversion efficiency improved by more than three orders of magnitude. Our air-clad device architecture boosts the sustainable intracavity pump power at cryogenic temperatures by suppressing the prominent photorefractive effect that limits cryogenic performance of TFLN, and reaches an efficiency of 1.02% (internal efficiency of 15.2%). This work firmly establishes the TFLN-superconductor hybrid EO system as a highly competitive transduction platform for future quantum network applications.

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Sub-terahertz bandwidth capactively-loaded thin-film lithium niobate electro-optic modulators based on undercut structure

Optics Express ◽

10.1364/oe.442091 ◽

2021 ◽

Author(s):

Xuecheng Liu ◽

Bing Xiong ◽

Changzheng Sun ◽

Jian Wang ◽

Zhibiao Hao ◽

...

Keyword(s):

Thin Film ◽

Lithium Niobate ◽

Electro Optic

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In-Situ Process and Simulation of High-Performance Piezoelectric-on-Silicon Substrate for SAW Sensor

Frontiers in Materials ◽

10.3389/fmats.2021.678658 ◽

2021 ◽

Vol 8 ◽

Author(s):

Rui Ma ◽

Weiguo Liu ◽

Xueping Sun ◽

Shun Zhou

Keyword(s):

Thin Film ◽

Lithium Niobate ◽

High Performance ◽

Electromechanical Coupling ◽

Substrate Material ◽

Electromechanical Coupling Coefficient ◽

Bonding Layer ◽

Saw Sensor ◽

Rayleigh Mode

This paper studied the manufacturing process of Piezoelectric-on-Silicon (POS) substrate which integrates 128° Y–X Lithium niobate thin film and silicon wafer using Smart-Cut technology. The blistering and exfoliation processes of the He as-implanted LN crystal under different annealing temperatures are observed by the in-situ method. Unlike the conventional polishing process, the stripping mechanism of the Lithium niobate thin film is changed by controlling annealing temperature, which can improve the surface morphology of the peeling lithium niobate thin film. We prepared the 128° Y–X POS substrate with high single-crystal Lithium niobate thin film and surface roughness of 3.91 nm through Benzocyclobutene bonding. After simulating the surface acoustic wave (SAW) characteristics of the POS substrate, the results demonstrate that the Benzocyclobutene layer not only performs as a bonding layer but also can couple more vibrations into the LN thin film. The electromechanical coupling coefficient of the POS substrate is up to 7.59% in the Rayleigh mode when hLN/λ is 0.3 and hBCB/λ is 0.1. Therefore, as a high-performance substrate material, the POS substrate has proved to be an efficient method to miniaturize and integrate the SAW sensor.

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