Scientists in Nizhny Novgorod, in the mid-Volga region, have come up with a new way of stepping up the output power of fiber laser systems. Multicore fibers are used to achieve that.

Fibers have long been part of compact laser radiation sources. These are predominantly single-core fibers that guide the light. Peak power to be obtained in laser systems based on such fibers is limited as the material of the fiber core has a tendency to deteriorate and fail at some point.

A team at the Institute of Applied Physics in Nizhny Novgorod is said to have been able to address this problem. A new multicore fiber came to replace the conventional single-core one, and the researchers have apparently managed to efficiently convert the radiation that comes out of the 25-core fiber into a high-quality laser beam.

In their experiments, the combining efficiency of the aggregate radiation (referred to as out-of-phase supermode) was 81%, with the quality of the output optical beam being comparable to that believed to be achieved in ideal conditions only. Assuming the ideal geometry of the multicore fiber (which the team keeps working on) and the scalability of such a system for a much larger number of cores (which appears absolutely possible), combining efficiency may reach 99%, the scientists said.

The research aims to pave the way for developing compact and very reliable fiber laser systems with a high enough peak power to be used in high-precision material machining and laser-aided microsurgery.