High-power pulses stabilize light sharing in multicore fiber

Researchers in Russia found that laser pulses behave very differently in a seven-core multicore fiber depending on power level. Low-power pulses scattered unpredictably, while higher-power pulses produced stable, even light sharing across all cores and a smoother beam pattern, a result that could matter for high-power laser systems and future fiber-based imaging and sensing.

Why it matters: - The findings point to a way multicore fibers could deliver more stable power sharing under high-power operation. - More even light distribution could help improve laser systems, beam combining, imaging and sensing. - The work also adds to the understanding of how light self-organizes in complex fiber structures.

What happened: - Researchers from the Institute of Automation and Electrometry SB RAS and Novosibirsk State University in Russia studied how laser pulses move through a seven-core multicore fiber. - The team sent narrowband laser pulses into the fiber’s central core and measured how output power split across the seven channels at different input powers. - The study was led by post-doctoral researcher Dr. Alena Yu. Kolesnikova under Prof. Sergey A. Babin. - The findings were published online in Opto-Electronic Advances on June 21, 2026.

The details: - At low power, the light distribution was random and unstable, with strong fluctuations in the power carried by each core. - At higher power, the light equalized across all seven cores and the fluctuations dropped sharply. - The output far-field pattern shifted from speckled and unstable to smoother and bell-shaped. - The equalized state stayed stable even when the fiber was bent or twisted. - The researchers combined experiments, numerical modeling and analytical treatment to track how the pulse evolved along the fiber. - The DOI for the paper is https://doi.org/10.29026/oea.2026.260036. - Prof. Babin said the beam stirring effect shows weakly coupled multicore fibers can self-organize under high-power excitation into a more stable output state. - Dr. Kolesnikova said the pulse does not just spread randomly and that its internal temporal structure helps average out power exchange between cores.

Between the lines: - The effect appears to be statistical, not accidental. - Modeling suggests high-power pulses break into many smaller sub-pulses, and their averaging over time drives the stable equal split of light. - Nonlinear phase accumulation changes the direction of energy transfer along the pulse and makes the output progressively more uniform. - That implies power itself can become a control knob for how multicore fibers behave.

What's next: - The researchers see a path toward more efficient high-power laser systems based on multicore fibers. - The results may support future work in light amplification, beam combining, imaging and sensing. - The broader implication is that optical systems can be designed for both higher power and greater resilience.