Hollow optical fibers increase polarization purity

Saving laser beam light in a pure polarization state plays a crucial role in interferometry to provide super accurate measurements of length, time, or other quantities. Optical fibers allow performing it, however, now the light is necessary to be directed through a vacuum for gold-standard purity that is considered to be too expensive and even impractical for all but the most specific applications.

Nowadays a team of researchers has presented a fiber optic technology included the fact that performance approaching that of a vacuum applying “antiresonant” optical fiber designed by a number of carefully produced hollow glass tubes installed around an air-filled core, as opposed to the glass-filled core of standard fibers. It should be noted that this fiber optic technology is regarded as highly beneficial for interferometric sensing because these optical fibers allow developing gravitational-wave detectors with arms an order of magnitude longer than today’s leading observatories.

It should be noted that standard glass optical fiber has disadvantages in transmitting huge amounts of data from one side of the world to the other in a split second, that is why it can not be used for accurate gyroscopes or the frequency combs. The thing is that such optical fibers have “tiny variations in the density of glass that scatter light in random directions and transfer power from one orthogonal polarization mode to the other—so limiting the polarization purity of light passing through the fiber.” Thus, the team has designed optical fibers with birefringence that restrains coupling between polarization modes by forcing the modes to travel at various speeds.

The researchers confirm that it is possible to improve the current limitations by at least two orders of magnitude by employing a hollow-core antiresonant optical fiber. To be more precise, the new optical fibers consist of glass tubes installed around its circumference with dimensions precisely chosen so that they couple to the laser beam light’s higher spatial modes. Thus, there is a single spatial mode in the core, with its two degenerate polarizations expanding almost entirely through the air. Finally, the researchers are developing different possible applications of fiber optic technology, for instance, new sensors and new methods of transmitting entangled photons.

Despite the fact that the antiresonant optical fiber has a high cost to create, it is real to reduce the cost of the fiber optic system similar to commercial polarization-maintaining glass fiber by increasing its production in large enough volumes. Moreover, several companies are distinguished that want to produce fiber optic systems based on this fiber optic technology. Herewith, it is planned to apply the polarization-pure optical fiber to design much bigger gravitational-wave interferometers resulting in yield interferometer arms as long as 40 km.

If you would like to obtain an optical fiber product, you should choose the Optromix company. Optromix is a provider of top quality special fibers and broad spectra optical fiber solutions. The company delivers the best quality special fibers and fiber optic cables, fiber optic bundles, spectroscopy fiber optic probes, probe couplers, and accessories for process spectroscopy to clients. If you have any questions or would like to buy an optical fiber, please contact us at info@optromix.com

Leave a Reply

Your email address will not be published.