Our path to a useful quantum computer

Taking a photonic approach, PsiQuantum leverages the trillions of dollars that have gone into the semiconductor manufacturing infrastructure to build Omega, our silicon photonic chipset.

Unlike competing technologies such as superconducting qubits and ion traps, which face significant scaling and manufacturability challenges, photonic qubits offer distinct advantages, including the ability to operate at higher temperatures and integrate seamlessly with standard optical fiber networks.

Omega: A manufacturable chipset

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A Manufacturable Chipset

Omega integrates new materials and advanced components, including high-performance single photon sources, superconducting single photon detectors, and a next-generation optical switch, into a commercial semiconductor fab. Omega represents a foundational shift in an industry that is often seen as being confined to research labs — a high-fidelity, scalable platform on which we are now actively building the world’s first useful quantum computers. Learn more in our manuscript published in Nature.

COMPONENTS TESTED > 10M
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Switch

By actively selecting successful trials, and reconfigurable two-qubit and single-qubit measurements, optical switches power fusion-based-quantum-computing. Our BTO fabrication process produces world-class switches, meeting the ultra-low-loss and high-speed requirements.

LOSS ~ 100mdB & DC VπL ~ 0.6 V.cm

Edge Coupler

Our utility-scale quantum computer is built from many photonic chips, networked using standard optical fiber. Chip-to-fiber coupling must be ultra-low-loss.

We’ve reduced industry standard losses from ~50% to ~1%, enabling die-to-die networking at error-correction-compatible levels.

COUPLING LOSS ~ 50mdB

Detector

We use single photons as our quantum information carriers.

AA typical lightbulb emits a billion-billion photons per second, and we detect them one at a time.

Superconducting films, biased near their transition point, enable efficient single-photon detection. We have introduced near perfect superconducting film production into semi-conductor manufacturing, and now produce detectors at scale.

We’ve extended this to photon-number resolution, critical for entanglement and error reduction.

EFFICIENCY ~ 99%

Interferometer

We encode information in the photon's path: top waveguide for one, bottom for zero.

To perform gates and build switches, we control light by coupling, crossing, and delaying waveguides in complex networks called inteferometers.

Our inteferometers achieve 99.999% fidelity, well within error correction thresholds.

EXTINCTION RATIO > 50dB

Source

Telecom wavelength single photons power our machine, and we generate them in pairs using on-chip optical resonators pumped by strong laser pulses. The pump light is 100 billion times stronger than the signal, so we filter it out while allowing our photons to pass through with approximately 1% level loss.

The result: the world’s most identical photons, produced at scale.

SOURCE PURITY ~ 99.5%

Inside a utility-scale quantum computer

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Wafer

Photonic components, including single photon sources, single-photon detectors, and an ultra-high-performance optical switch, are fabricated in a high-volume semiconductor foundry on standard silicon wafers.

Photonic qubits avoid exotic materials and manufacturing processes and are able to leverage the existing reliability, volume and precision of standard semiconductor manufacturing processes.

WAFERS TESTED >5K
DEVICES TESTED >1M
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Chip

Photonic qubits are implemented by repurposing integrated photonics technology, originally developed for telecom and datacenter networking applications.

Entangled states — specially designed to implement quantum error-correcting codes — are created and measured using fusion gates.

Nondeterministic photon sources and gate operations are made scalable via a combination of multiplexing and loss-tolerant error correcting codes

SINGLE-QUBIT FIDELITY 99.99% 1
TWO-QUBIT FIDELITY >99% 2
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Package

Photonic chips are integrated with cryogenic control electronics into a manufacturable package.

Despite the fact that some of these packages must be operated at cryogenic temperature, we are able to use conventional technologies — PCBs, copper heat sinks and bump bonding. As a result, PsiQuantum can leverage conventional contract manufacturing to build large numbers of packages quickly.

Photonic qubits can be networked and modularized using standard optical fiber, without transduction — a huge advantage at scale.

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Blade

Building a utility-scale quantum computer requires installing thousands of photonic packages. We adopt a proven model from classical computing: modular, rack-based infrastructure. Our addition? Adapting it for cryogenic operation.

Our blade is the scalable unit of cryogenic quantum computing racking. It houses many individual photonic-packages networked together with fiber and control signals.

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Cryo Rack

Photonic qubits do not feel heat, do not decohere and can be operated at high fidelity at room temperature.

While the superconducting detectors needed for high-efficiency readout of photonic qubits do require cryogenic cooling, they operate at ~4K––100x hotter relative to ~10mK (e.g. superconducting qubits).

PsiQuantum is building and testing cryogenic racks with thousands of times more cooling power than the largest dilution refrigerators ever built or operated.3 Because of the higher operating temperature of photonic qubits, these cryostats can also be surprisingly simple and can be built using existing cryogenic technology.

COOLING POWER ~100W
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Utility-Scale Quantum Computer

Most architectures for quantum computing will require a data center-like facility in order to deliver enough qubits for commercially useful applications and to scale far beyond.

In 2024, PsiQuantum announced two landmark partnerships with the Australian Federal and Queensland State governments, as well as the State of Illinois and the City of Chicago, to build its first utility-scale quantum computers in Brisbane and Chicago. Recognizing quantum as a sovereign capability, these partnerships underscore the urgency and race towards building million-qubit systems. In 2025, PsiQuantum will break ground at both sites, where the first utility-scale, million-qubit scale systems will be deployed.

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