Netherlands-headquartered photonic quantum computing hardware company QuiX Quantum has detailed its new Feed-Forward Control Unit (FFCU), a high-performance hardware component developed for the company’s universal photonic quantum computing architecture. While it is perhaps no surprise that photonic quantum computing requires rapid adaptive control, it’s not as easy to graph the how factor here, so let’s unpack the quantum state and shine some light on the photonics within.
A photonic quantum computer uses light particles, or photons, as qubits to process information through optical circuits at extreme speeds.
A FFCU is designed to help the system respond to quantum measurements in real time, an essential requirement for photonic quantum computers that encode and process information in single photons moving through optical circuits at extremely high speeds.
How feed-forward control works
Feed-forward control anticipates disturbances by measuring them before they affect a system, allowing for preemptive adjustments to maintain a desired state rather than reacting to errors after they have occurred.
It is especially important for reaching universality in measurement-based quantum computing, where computation is carried out through a sequence of measurements and the outcome of one measurement can determine how later operations are performed.
NOTE: Universality refers to a system’s ability to perform any possible computational task or logic operation given enough time and resources.
Single-photon detector signals
The FFCU performs this step at the hardware level by converting single-photon detector signals into control actions on photonic integrated circuits.
The FFCU is part of QuiX Quantum’s broader quantum computing architecture, which brings together photon generation, multiplexing (a term NICAM fans might know from the audio world – and here also used to explain a technique used to increase the probability of generating a single photon or achieving a specific quantum state by running multiple operations in parallel), state generation, measurement, photonic assembly control and feed-forward control into a single photonic quantum computing stack.
QuiX Quantum is working on its first-generation single-photon-based universal quantum computer, with the FFCU serving as one of the system-level components needed to support adaptive, programmable photonic quantum operations.
Considered a critical long-term goal by quantum hardware developers, a universal quantum computer will be able to run a broad set of quantum algorithms that can support a wider range of scientific, industrial and commercial applications.
Controlling photons, in real time
“Universal photonic quantum computing requires more than high-quality photonic chips. It requires a complete system stack that can generate, route, measure and control photons in real time,” said Stefan Hengesbach, CEO of QuiX Quantum. “Our FFCU is a critical step in building that stack. It turns photon measurement outcomes into immediate control actions on photonic integrated circuits.”
QuiX Quantum’s FFCU combines FPGA-based digital processing with a custom analogue front-end to support deterministic control of Mach-Zehnder interferometers on integrated photonic circuits.
The current rack-mounted system includes two FPGA modules connected by a high-speed, low-latency bus, with 32 inputs, 32 outputs and a reported latency of approximately 150 nanoseconds from detector input signal to settled output voltage.
The speed of light, for 150 nanoseconds
“Fast feed-forward is a prerequisite for universal photonic quantum computing because measurement-based architectures require the system to detect, decide and reconfigure the optical path in real time,” said Andrew Roos, vice president of R&D for QuiX Quantum. “To put that timing in perspective, in 150 nanoseconds light travels only about 30 meters in telecom fibre. That is the window in which the system has to make a decision and adapt the photonic circuit. This is not conventional control electronics – it is operating close to the physical limits at which information can move.”
As esoteric as this sounds, the company insists there is commercial relevance here and points to McKinsey’s Quantum Technology Monitor 2026, which reports that more than 300 organisations around the world are actively collaborating with quantum technology companies and estimating that quantum computing could create up to Euros 2.32 trillion in economic value worldwide by 2035.