LUMEN project explores visible fiber laser technology

Visible fiber laser technology in the 1–10 watt range remains a critical gap in optical instrumentation, silica-based sources simply cannot operate in the visible spectrum. The LUMEN project, launched in May 2025 and funded under the France 2030 Plan, addresses this challenge using fluoride glass fiber, a material pioneered in Brittany over 50 years ago. Developed by a six-partner French consortium including Oxxius, the project targets high-impact applications such as super-resolution microscopy, DNA sequencing and quantum research.

The LUMEN project is built on previous developments in silica-based infrared fiber lasers, which have found applications in sectors such as automotive manufacturing, ophthalmology, and materials processing.

However, silica fibers are not suitable for use in the visible spectrum. To address this, the LUMEN project is working with fluoride glass fiber technology, a material first developed in Brittany more than 50 years ago.

These fibers are better adapted to visible wavelengths and are being used as the basis for the project’s work.

Key Technical Challenges in Visible Fiber Laser Development

LUMEN focuses on adapting several established technologies from silica fibers to fluoride glass. These include double-clad fiber architectures, fiber Bragg gratings (FBGs), and pump/signal combiners. The project also considers practical challenges such as power handling, the durability of components, and long-term system reliability.

A Six-Partner Consortium to Industrialize Visible Fiber Lasers

The project brings together several partners with complementary expertise:

Le Verre Fluoré – responsible for designing specialty fibers and fiber-based modules
Oxxius – develops the laser systems
Alphanov – works on optical component development and industrialization
Université Jean Monnet (Saint-Étienne) – develops FBGs
CORIA (Rouen) – focuses on pump/signal combiners
CIMAP (Caen) – works on optimizing laser configurations

Visible Fiber Laser Applications: Microscopy, DNA Sequencing and Quantum Research

There are currently limited options for compact and efficient laser sources in the visible spectrum that operate in the 1–10 watt power range. Yet, this level of output can be useful in a number of areas, including super-resolution microscopy, DNA sequencing, and quantum control of atoms.

The LUMEN project aims to provide laser technologies that meet these specific needs, with potential relevance in fields such as biomedical imaging and quantum research.

Next Steps: Toward a Complete Visible Fiber Laser System

The project is at an early stage. Current efforts are centered on fiber design and fabrication, component development, and the creation of initial blue pump modules. Work is underway to optimize rare-earth-doped fluoride fibers, adapt components to this material platform, and prepare for system integration.

— Updated on Nov. 4, 2025 — On October 29, 2025, a technical progress meeting was held to review the first six months of the LUMEN project. We were hosted by Emmanuel Marin (Professor and technical point of contact) at the Hubert Curien Laboratory of Jean Monnet University in Saint-Étienne.

Following a morning of technical discussions on the project’s progress and the challenges encountered (during which all partners were able to contribute) a visit took place in the afternoon to discover the laboratory’s work and equipment, particularly related to Fiber Bragg Grating (FBG) inscription, a key component of the project, on optical fibers.