Nonlinear laser beams in spatial systems

A team of researchers from Switzerland has succeeded to produce high-energy, ultrashort pulses with single-mode laser beam originated from nonlinear beam cleaning in a multimode laser system cavity. The thing is that previously mode-locked fiber lasers applying single-mode optical fibers were supposed to just temporal modes.

To be more precise, mode-locked single-mode fiber laser systems are considered to be very advantageous. The benefits include high-gain doping, intrinsically single-spatial mode, and compact setups. Nevertheless, when it comes to high power, mode-locked fiber lasers have some disadvantages, for instance, high nonlinearity because of the compact core size of optical fibers.

Thus, a team of researchers from Switzerland has presented a novel technique for producing high-energy, ultrashort pulses with single-mode laser beam quality. They develop nonlinear laser beam cleaning in a multimode laser system cavity. It should be noted that the conventional technique supposes the generation of low-power ultrashort laser oscillators to solve the problem. 

Then it is necessary to increase the laser beam power levels by several amplifiers but the process of external amplification makes the cost and complexity higher. Nowadays researchers prefer applying multimode optical fibers (graded-index ones) in fiber laser systems because of their low modal dispersion and periodic self-focusing of the light inside.

The researchers claim that it is possible to perform spatial laser beam cleaning, wavelength conversion, and spatiotemporal mode-locking using graded-index multimode optical fibers. The thing is that the technique of spatiotemporal mode-locking is a relatively new one that allows for creating ultrashort pulses by fiber lasers.

The technique produces “a balance between spatial and temporal effects within a multimode laser system cavity, which supports multiple paths to guide light.” The thing is that a big multimode core leads to a decrease of the cavity nonlinearity, herewith, the fiber laser can achieve high pulse energy without external amplification. Nevertheless, high power mode-locked fiber laser systems suffer from a low-quality output laser beam because of multimode fibers.

Finally, the researchers have tested the developed fiber laser technology and demonstrated nonlinear beam cleaning in a multimode laser for the first time. The nonlinear laser beam cleaning promotes the creation of high-energy, ultrashort pulses with single-mode beam quality. The fiber laser technology directs a high-quality laser beam when mode-locking is reached.

If you are looking for a compact highly-efficient laser system, the Optromix company is ready to manufacture it. Optromix is a manufacturer of laser systems, optical fiber sensors, and optical monitoring systems. We develop and manufacture a broad variety of fiber lasers, high-powered fiber lasers, and other types. We offer simple laser products, as well as sophisticated fiber laser systems with unique characteristics, based on the client’s inquiry. 

We manufacture laser modules using our technologies based on the advanced research work and patents of the international R&D team. Laser processes are of high quality, high precision, easily-automated manufacturing solutions that provide repeatability and flexibility. If you have any questions or would like to buy a fiber laser system, please contact us at

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