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Breakthrough in vortex laser technology
Researchers from the U.S have presented a micro laser system that makes it possible to dynamically tune to numerous distinct OAM modes. They confirm that the OAM modes of fiber lasers are measured by a chip-based detector. Two laser technologies have been combined in this research, resulting in the first tunable, chip-based vortex fiber laser system.
Why vortex laser systems matter
These vortex laser systems are named for the manner in which their light twists around their axis of movement.
Previous limitations
Although the laser technology is not new, it has some limits to transmitting a single, pre-set OAM mode, resulting in inefficient encoding of more information.
Detector challenges
Additionally, current detectors use complex filtering methods applying bulky components that make them impossible to integrate directly onto a chip; they are considered to be incompatible with most practical optical communications approaches.
Advancements in fiber lasers and detectors
Since fiber lasers and detectors have now become more accurate, they both allow consistently emitting and distinguishing between various amplitude levels, leading to more data to be included in the same signal.
Additional laser beam qualities
More sophisticated laser systems and detectors enable changing other qualities of laser beam light, for instance, its wavelength, which corresponds to a color, and its polarization, which is regarded as the orientation of the wave’s oscillations relative to its direction of travel.
Research from Pennsylvania
The research on a dynamically tunable fiber laser system based on this technique is presented by the researchers from Pennsylvania.
Microring laser system
According to the research, the first step was working with a “microring” laser system that includes a ring of semiconductor, only a few microns wide, through which the laser beam light circulates indefinitely as long as power is supplied.
Coupling SAM and OAM
“Asymmetry between the two control arms allows for the SAM of the resulting fiber laser to be coupled with OAM in a particular direction.”
Helical pattern of OAM modes
Instead of simply rotating around the axis of the laser beam, the wavefront of this fiber laser system orbits that axis and therefore travels in a helical pattern.
Chirality and information expansion
OAM mode of the laser system follows its chirality, the direction those helices twist, and how close together its twists are. The new fiber laser technology has already been tested and demonstrated the ability to emit five distinct OAM modes, leading to expanding the information channel of such fiber lasers by up to five times.