g2-Zero

g2-zero.com ↗ ·Madrid ·Pre-seed

g2-Zero is a Madrid-based quantum photonics deeptech company that develops "plug & play" single photon sources — electrically driven, vibration-resistant and alignment-free semiconductor devices for quantum communications (QKD), quantum computing and quantum sensing. It is a spin-off of the Institute of Micro and Nanotechnology of the Spanish National Research Council (IMN-CSIC) and the Universidad Politécnica de Madrid (UPM), operating from Parque Científico de Madrid, and closed a pre-seed round in April 2024 (~€315K) led by FI Nvest with Hamamatsu Photonics' corporate VC arm. It was one of 44 companies chosen from 1,300+ applicants for the first cohort of NATO's DIANA accelerator (via Deep Tech Lab – Quantum in Copenhagen) and joined ESA BIC Madrid Region and the MadQuantum accelerator in 2025.

Founded

2022

Founders

Total funds raised

€315K

SectorsQuantum technology, Photonics, Semiconductors, Deeptech, Quantum communications, Cybersecurity Start-up MapDeeptech & Hardware › Semiconductors, compute & AI infrastructure

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Founders

Benito Alén

CEO & Co-founder

José Manuel Llorens

CSO & Co-founder

José María Ulloa

COO & Co-founder

Global models 5

Quantum Source

Israel · www.quantum-source.com ↗

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Quandela

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~$75MComparable

Nu Quantum

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University spin-off that started with single-photon source and detector hardware and now sells photonic networking hardware for quantum communication and computing.

~$70MComparable

Sparrow Quantum

Denmark · sparrowquantum.com ↗

Spin-off from the Niels Bohr Institute selling plug-and-play semiconductor single-photon sources to photonic quantum computing and communication customers, the closest direct match.

~$30MComparable

Aegiq

United Kingdom · www.aegiq.com ↗

Spin-off from the University of Sheffield developing quantum-dot single-photon sources for secure quantum communications and photonic quantum computing.

~$10MComparable

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Notes: Most funded first

Investors 4

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FI Group

fi-group.com

Led Pre-seed 2024 Spain

B5tec founding partners

Pre-seed 2024 Spain

Hamamatsu Photonics Corporate Venture Capital

cvc.hamamatsu.com ↗

Pre-seed 2024 Japan

Deep Tech Lab – Quantum

deeptechlab.bii.dk ↗

Investor Denmark

Funding rounds 1

Date	Round	Amount	Lead
2024-04-22	Pre-seed (estimated)	€315K	FI Group +2 more

News 5

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Published	Article
2026-06-23	g2-Zero: Making Quantum Light Practical, Plug-and-Play, and Ready to Scale ↗ Tech Tour 2026-06-23
2026-02-27	PhotonHub Scaling Club 2.0 Builds on €81M Investment Momentum ↗ Tech Tour 2026-02-27
2024-05-06	Invests in g2-Zero ↗ Hamamatsu Photonics Corporate Venture Capital 2024-05-06
2024-04-21	Los chips cuánticos de investigadores del CSIC que salen del laboratorio a buscar aplicaciones en el mundo real ↗ El Español / Invertia Disruptores 2024-04-21
2023-11-30	The first six companies enter the Deep Tech Lab - Quantum start-up accelerator at BII to unlock the potential in quantum science ↗ PR Newswire (BioInnovation Institute) 2023-11-30