Key points
- Researchers ensure stable laser performance across temperature swings of 100 degrees Celsius
- Technological breakthrough made in wide-temperature fibre laser
- Ytterbium plays a critical role in this advancement
ISLAMABAD: Chinese researchers have developed a two-kilowatt (kW) fibre laser capable of operating without the need for heating or cooling systems in some of Earth’s harshest environments – ranging from minus 50 degrees Celsius in the Arctic to 50 degrees Celsius in the Sahara Desert.
Designed for rapid and ultra-portable deployment in both defence and industrial settings, the device marks a significant contrast to comparable systems such as Europe’s HELMA-P or India’s IDDIS. These typically require lorry transport and container-sized cooling units to achieve a drone kill range of 1km (0.62 miles), according to the South China Morning Post.
The breakthrough comes from a team led by Chen Jinbao, vice-president of the National University of Defence Technology (NUDT) and a nationally recognised expert in high-energy lasers. The researchers addressed a longstanding challenge: ensuring stable laser performance across temperature swings of 100 degrees Celsius.
Bold design decisions
Key to the innovation are bold design decisions, such as the use of 940-nanometre pump lasers with minimal thermal drift. These pump lasers inject light directly via nine forward and 18 backwards fibre-coupled diodes.
The team also placed pump combiners outside the resonator to separate heat-sensitive parts from thermal influence. Furthermore, coiling ytterbium-doped fibre to approximately 8cm in diameter suppresses unwanted lightwaves.
“We have made a technological breakthrough in wide-temperature fibre laser performance,” wrote Chen and his colleagues in a peer-reviewed paper to appear in Higher Power Laser and Particle Beams, a Chinese-language journal, in July. The paper is already available online.
Dual-clad optical resonator
At the heart of the laser is a dual-clad optical resonator: ytterbium-doped fibres held between two highly reflective gratings, which reflect 99 per cent of the light. When pumped, ytterbium ions release photons that are amplified into a high-powered 1,080nm laser beam, which is then filtered and focused using quartz lens caps.
In laboratory simulations replicating Arctic-to-desert temperature shifts, the laser consistently delivered over 2kW output – peaking at 2.47kW at 20°C, with an impressive 71 per cent efficiency and near-ideal beam quality.
Ytterbium, a rare earth element heavily sourced from China – which controls more than two-thirds of the global supply – plays a critical role in this advancement. Its unique atomic structure allows for highly efficient energy conversion and strong resistance to thermal quenching.
Operating range
The implications of the research are significant. While equivalent systems in other countries require entire shipping containers for operation, NUDT’s prototype is approaching the size of a suitcase.
“To ensure stable output, conventional fibre lasers rely on integrated cooling systems to control internal temperatures, restricting their operating range to near room temperature,” the researchers explained.
“However, with applications broadening, demand is rising for fibre lasers that can operate briefly and stably in any thermal environment,” they added.
“Fibre lasers combine high efficiency, low cost, and compact form – making them ideal for widespread use in industrial machining, optoelectronic defence, and precision cutting.”
Chen’s team concluded by stating they would continue developing the technology, aiming for even higher output power and a broader operational temperature range.
