Xanadu has taken a key step toward scalable fault-tolerant quantum computing by demonstrating the generation of error-resistant photonic qubits — known as GKP states — on a silicon-based chip platform, a first-of-its-kind achievement. The milestone positions the Toronto-based quantum startup closer to building a modular and networked photonic quantum computer, a device that uses photons, rather than electrons, to perform calculations, according to the paper and a company statement. By encoding quantum information into complex photon states that can withstand noise and loss, the work directly addresses one of the central obstacles to quantum scalability: preserving fragile quantum data as systems grow in size and complexity. Xanadu’s researchers generated what are known as Gottesman–Kitaev–Preskill (GKP) states — structured quantum states made of many photons arranged in specific superpositions. These states encode information in a way that makes it possible to detect and correct small errors, such as phase shifts or photon loss, using well-known quantum error correction techniques. Xanadu’s experiment demonstrates that GKP states can be produced directly on-chip using integrated photonics, paving the way for scalable manufacturing. The system is based on silicon nitride waveguides fabricated on 300 mm wafers, a format common in commercial semiconductor manufacturing. These waveguides exhibit extremely low optical losses, a critical requirement for preserving quantum coherence over time. In addition to the waveguide platform, the setup included photon-number-resolving detectors with over 99% efficiency, developed in-house by Xanadu. These detectors can distinguish between one photon and many, a capability essential for preparing and verifying complex photonic states like GKP. High-precision alignment, custom chip mounts, and loss-optimized fiber connections ensured that the quantum states could be routed and measured without degrading the delicate information they carried.