Photonics

The photonic qubit of the future

June 4, 2025

banner image: The photonic qubit of the future

Xanadu's latest hardware breakthrough.

Today, we announced the first ever demonstration of GKP qubits on an integrated photonic chip. This is a significant breakthrough in creating qubits that are robust and error resistant, and was published in Nature. This achievement builds upon our other recent hardware milestone, Aurora, where we built a quantum computer that was modular, scalable, and networked.

During the publication process for our paper “Integrated photonic source of Gottesman-Kitaev-Preskill qubits”, the editors of Nature invited us to contribute a Research Briefing.

Have a read of that summary to share with us the excitement behind this critical milestone on Xanadu’s mission to build quantum computers that are useful and available to people everywhere.

Laser pulses, which operate at an optical wavelength (1550 nm), enter the photonic chip on the left side of the diagram. These pulses of light propagate through our custom-made chip, which comprises waveguides made from our 300 mm, ultra-low loss silicon nitride wafers, connected using our state-of-the-art optical packaging. The laser light then passes through “Squeezers” to be converted into more useful (non-Gaussian) states, and is entangled in the “Unitary” using a programmable linear interferometer. A few steps of light filtering are present between the stages on the chip to help separate the processed light from the pump laser light. After entanglement, the resulting state exits the chip and enters a photon number resolving detector (PNRs). The PNRs validate that the correct multiphoton state was generated through Gaussian boson sampling and when the right pattern is detected, the state is accepted and encoded as a GKP state.
Diagram of the custom chip that generates GKP qubits in Xanadu's architecture.
The central plot shows the intensity of the Wigner function associated with the GKP qubits in both q and p quadratures. On the sides, the projections along q and p quadratures are shown, where well-defined peaks are seen and binary state encodings are made possible encoded as a GKP state.
The measured quantum state of our GKP qubit, showing the grid structure needed for computation.

Published on June 4, 2025

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