Translation. Region: Russian Federation –
Source: Novosibirsk State University –
An important disclaimer is at the bottom of this article.
A practical method for achieving the shortest pulse duration in all-fiber lasers was developed by Sergei Kobtsev, Doctor of Physical and Mathematical Sciences and Head of the Department of Laser Physics and Innovative Technologies at Novosibirsk State University. The results of his work in this area were published in the article "Production of ultrashort pulses in fiber lasers" ("Obtaining ultrashort pulses in fiber lasers"). The article became one of the most downloaded publications of the journal "Journal of the Optical Society of America B" in July-September 2025. The research was conducted within the framework of the project "New fiber short-pulse laser systems incorporating advanced composite materials, intelligent technologies and metrological extensions," supported by the Ministry of Science and Higher Education of the Russian Federation.
Fiber lasers are a promising type of laser, distinguished by improved key user parameters—the elimination of the need for precise laser cavity tuning, effective natural heat dissipation, efficient generation, and compactness. However, producing ultrashort pulses in these lasers is a challenging task due to increased dispersion and nonlinearity, often requiring the use of bulk optical elements. Such elements significantly reduce the advantages of fiber (or solid fiber) lasers.
"Sometimes, fiber lasers are used to describe combined configurations containing only a minority of fiber components, while the majority of the optical elements are bulk. Such combined fiber-bulk lasers lose important advantages associated with solid-fiber lasers. Although such combined fiber-bulk lasers can produce pulses lasting a few femtoseconds, these configurations differ little from traditional solid-state bulk lasers with their inherent drawbacks. We were interested in the minimum pulse duration possible in solid-fiber lasers, especially with fixed polarization. It turned out that such lasers can generate pulses of picosecond duration and longer," explained Sergey Kobtsev.
The results of this work are of interest to a wide range of specialists using fiber components in research and development. The ability to generate picosecond light pulses in all-fiber lasers expands their applications while maintaining the advantages of this type of laser. Given the increasing prevalence of all-fiber lasers, their generation characteristics are of great interest.
"Fiber lasers are undergoing rapid development. A few years ago, it seemed that fiber lasers could replace all other laser types due to their significant advantages. However, numerous studies have shown that these advantages are inherent not to all fiber lasers (combined, etc.), but specifically to all-fiber lasers. It became interesting to determine at what pulse durations the all-fiber configuration could be combined with short pulses. A detailed study of the problem revealed a solution: starting with pulse durations in the picosecond range, they can be generated in all-fiber lasers with fixed polarization. The mechanism for generating ultrashort pulses is also important, but a fundamental solution has already been demonstrated," explained Sergey Kobtsev.
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