Work

Spectrum collapse in a seven-core fiber laser with wavelength-shifted fiber Bragg gratings: modeling and comparison with experiment

Year: 2026

Type: article

Abstract: Multicore fiber is a prospective medium for high-power lasers. All-fiber cavities based on fiber Bragg gratings (FBGs) inscribed by femtosecond pulses in uncoupled cores generate beams independently at wavelengths defined by the individual FBG reflection. However, separate core generation spectra collapse into a single narrow and stable line at strong optical coupling between the cores. The developed model shows that the collapsed spectrum linewidth depends on the number of cores, their coupling strength and the geometric-mean reflection width of individual FBGs. It is revealed that physical mechanisms and quantitative features of linewidth broadening defined by spatial hole burning and Kerr effects are sufficiently modified in comparison with single-core lasers. A performed comparison of the theory with experiment demonstrates a fairly good correspondence of key characteristics, namely the generation wavelength, spectrum shape and the linewidth value depending on power. An extreme linewidth narrowing is predicted for a high-power multicore fiber laser with a greatly increased number of cores and their coupling strength.

Source: High Power Laser Science and Engineering

DOI: 10.1017/hpl.2026.10157

Authors: Alena Yu. Kolesnikova, Alexey G. Kuznetsov, Evgeny V. Podivilov, Sergey A. Babin

Institutions: Novosibirsk State University, Institute of Automation and Electrometry

Language: English

Topic: Photonic Crystal and Fiber Optics

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,900

OpenAlex ID: W7162036948