Transverse mode-encoded quantum gate on a silicon photonic chip

Abstract

As an important degree of freedom (DoF) in integrated photonic circuits, the orthogonal transverse mode provides a promising and flexible way to increasing communication capability, for both classical and quantum information processing. To construct large-scale on-chip multimode multi-DoF quantum systems, a transverse mode-encoded controlled-NOT (CNOT) gate is necessary. Here, through design and integrate transverse mode-dependent directional coupler and attenuators on a silicon photonic chip, we demonstrate the first multimode implementation of a two-qubit quantum gate. With the aid of state preparation and analysis parts, we show the ability of the gate to entangle two separated transverse mode qubits with an average fidelity of $0.89\pm 0.02$ and the achievement of 10 standard deviations of violations in the quantum nonlocality verification. In addition, a fidelity of $0.82\pm 0.01$ was obtained from quantum process tomography used to completely characterize the CNOT gate. Our work paves the way for universal transverse mode-encoded quantum operations and large-scale multimode multi-DoF quantum systems.

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• Photonic quantum technologies
• Integrated Photonic Quantum Technologies
• Silica-on-Silicon Waveguide Quantum Circuits
• Beating the channel capacity limit for linear photonic superdense coding
• Second harmonic generation in nano-structured thin-film lithium niobate waveguides
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Cited by in corpus (4)

• Two-qubit quantum photonic processor manufactured by femtosecond laser writing
• Quantum teleportation of an elemental silicon nanophotonic CNOT gate
• Global calibration of large-scale photonic integrated circuits
• Higher-dimensional symmetric informationally complete measurement via programmable photonic integrated optics