QphoX is a Delft-based quantum technology company developing quantum transducers and quantum modems that connect superconducting quantum processors over optical networks. Its technology performs quantum transduction, converting quantum information between microwave and optical frequencies, with the aim of enabling distributed, scalable quantum computing and forming a foundation for a future quantum internet. QphoX was founded in 2021 as a spin-off from the Quantum Nanoscience department at TU Delft by Simon Groeblacher, Robert Stockill and Frederick Hijazi.

In March 2026 the company launched its Quantum Transducer as a commercial product, a device that allows quantum information to travel through optical fiber networks at room temperature over large distances. IBM will work with the Quantum Transducer to connect superconducting qubits via its Quantum Networking Unit test devices. The company also offers an Optical Control System for delivering RF signals into cryogenic environments, and in March 2026 it announced results with Bluefors on optical control of superconducting qubits.

QphoX's collaborations include a partnership with Welinq on optical interconnects for superconducting processors (2025), a multi-channel optical readout project with Rigetti and the UK National Quantum Computing Centre (2025), and a $5.8 million contract from the US Air Force Research Laboratory with Rigetti to co-develop quantum transducers for a superconducting network (2025). It is also a project partner in the Photonics for Quantum (P4Q) pilot, leads a work package in the SUPREME superconducting quantum pilot line, and takes part in the Meet-Q project with Welinq and Sorbonne University as well as the Superspin project linking a superconducting quantum computer to a spin-based quantum memory.

QphoX raised a €2M seed round in 2021, received an EIC Accelerator grant of €6.5M, closed an €8M round in January 2024 led by QDNL Participations, and in November 2025 was selected for a €10M equity investment from the EIC STEP Scale-Up scheme. The team numbers roughly 40 to 50 people across several countries.