Quantum Chips Operating at Room Temperature: The Photonic Revolution Begins with Glass

1. Prologue: The Dawn of Quantum is a Glass-Colored Sunrise

Quantum computers have long been hailed as "machines that will change the world." However, existing platforms like superconductors and ion traps have faced challenges due to the high costs of practical implementation, requiring ultra-low temperature equipment and complex vacuum systems.

However, in July 2025, an EU research team centered in Milan, Italy, announced a photonic quantum chip using laser writing technology to directly inscribe optical waveguides onto a glass substrate, changing the landscape. The qubits are not electrons or ions, but **photons**. They operate at room temperature, transmit signals at the speed of light, and have significantly lower energy loss. It is truly a breakthrough heralding a "dawn."phys.org

2. What is the QLASS Project?

Leading this breakthrough is the QLASS (Quantum Glass-based Photonic Integrated Circuits) project, coordinated by Politecnico di Milano (PoliMi). Eleven research institutions, including universities, research institutes, and startups from Italy, France, and Germany, have come together, gaining spotlight after being detailed in the EU Research & Innovation Magazine "Horizon." The goal is simple: to realize a reconfigurable photonic quantum processor with over 200 modes using glass quantum chips by 2026.phys.org

The core company is the Italian startup Ephos. The company has just opened the world's first fab dedicated to glass quantum chips in the suburbs of Milan, having raised $8.5 million from NATO DIANA and Western venture capitalists.reuters.com CEO Andrea Rocchetto states, "Glass is the best material for trapping photons." Glass has optical losses less than one-tenth of silicon, and because it operates at room temperature, no refrigeration is needed—power consumption is significantly lower.

3. Core Technology: Femtosecond Laser Writing

Ephos's proprietary technology involves "directly writing" three-dimensional waveguides inside glass using a femtosecond (10⁻¹⁵ second) laser. This method uses a titanium-sapphire laser to locally modulate the refractive index, sculpting nanoscale "paths of light" that confine light. Unlike traditional silicon photonics, which is constrained to planar (2D) wiring, glass allows for 3D wiring with free curves in the vertical direction. As a result, scaling from 200 modes→400 modes can theoretically be achieved with only a mask change.phys.org

By combining with SNSPD (Superconducting Nanowire Single-Photon Detectors) provided by Germany's Pixel Photonics, the aim is to achieve lossless detection of single photons. Furthermore, France's Unitary Foundation France is developing an open-source quantum SDK, while the University of Montpellier group is handling quantum simulations of lithium-ion batteries. This division of labor is a microcosm of the "self-sufficiency of the supply chain within Europe" advocated by the EU Chips Act.phys.org

4. Why Glass?—Advantages in Both Environment and Cost

• Energy Saving: Operates at room temperature, eliminating the need for dilution refrigerators essential for superconducting chips (over 10 million yen in annual electricity costs).

• Low Carbon: Glass manufacturing can reduce CO₂ emissions by 75% compared to the silicon front-end process.wsj.com

• Yield: Laser direct writing significantly reduces photolithography processes, lowering defect rates.

• Cost: According to Ephos, the manufacturing cost per 12-inch equivalent substrate is one-third that of silicon photonics.

Furthermore, since photons are less prone to decoherence at room temperature, it is reported that error correction overhead can be reduced by over 20%. Although still in the research stage, the materials are in place to push towards practical quantum supremacy (the threshold where quantum computers surpass the fastest classical machines).

5. Industrial Applications: From Battery Design to AI Inference Acceleration

1. Next-Generation Battery Simulation
   The University of Montpellier is tackling the optimization of electrolytes by solving lithium diffusion paths using variational quantum algorithms (VQA). It is reported that a 50-mode optical chip implemented in the lab achieved a 30-fold speedup compared to classical methods (according to a non-public preprint).

2. Drug Discovery
   Using single-photon interference for Hamiltonian encoding, the conformational energy difference of candidate anticancer molecules is calculated with picochem precision.

3. AI Accelerator
   Mathematical optimization (QAOA) and linear algebra (HHL algorithm) are estimated to be 100 times more energy-efficient than GPUs. This directly contributes to the decarbonization of data centers.wsj.com

6. The "Quantum Glass Revolution" Seen on Social Media

“The QLASS project just secured €6 M from the EC to push photonic quantum chips made of glass. Europe is finally playing to its strengths! 🌍💡” ― The Quantum Insider@QuantumDaily (X)twitter.com

“Politecnico di Milano coordinates #QLASS to harness photon quantum properties. Proud to be part of this journey!” ― Politecnico di Milano Official (X)twitter.com

“Sviluppare un pc quantistico che funziona a temperatura ambiente: obiettivo QLASS.” (Developing a quantum PC that operates at room temperature: that's QLASS's goal) ― ANSA Scienza&Tecnica (X)twitter.com

“NATO-backed Ephos raises $8.5 M to build world’s first glass-based quantum photonic fab. The race just got brighter!” ― Quantum Insider@QuantumDaily (X)twitter.com

On social media, discussions are heating up with hashtags like "#PhotonicChips," "#ClimateTech," and "#DeepTechEU." Particularly among the younger generation, who emphasize decarbonization, there are many positive comments like "No refrigeration is divine" and "The era of quantum = eco has arrived," although concerns about "Isn't glass fragile?" are also being raised.

7. Challenges: Scaling and Standardization

The biggest hurdle is "mass production of single-photon sources and detectors." SNSPDs still require cryogenic environments, making the development of room-temperature SNSPDs an urgent task. Moreover, quantum applications require tight integration between the algorithm layer and the hardware layer, and if the standardization of software APIs lags, the ecosystem will be fragmented. The EU aims to procure 20% of quantum chip shipments domestically by 2030, but achieving this will require both open source and patent pools.phys.org

8. Future Outlook: Photonics x Green x Europe-Led

With the EU Chips Act extending its reach to the quantum field, photonic quantum has become a trump card that simultaneously satisfies the two geopolitical agendas of "decarbonization" and "supply chain independence."

If QLASS completes a 200-qubit class demonstration machine by 2026, there is a high possibility that Europe's first quantum-accelerated supercomputer (under the jurisdiction of EuroHPC JU) will be installed in Milan. The roadmap aiming for 1,000 qubits within five years of completion and 1 million qubits within ten years is beginning to make existing superconducting forces break a sweat.

9. Epilogue: The Quantum Universe Expanding Within Glass

Just as silicon became the ruler of electronics in the 1960s, in the late 2020s—light and glass may become the foundation of quantum information processing."Cracking the quantum code"—this catchphrase is no exaggeration. Now, the faint light trapped within a shard of glass is becoming the key to solving humanity's massive computational problems.The future of quantum is quietly increasing its brilliance within transparent glass.