Last week, China announced the successful testing of their laser experiment, which they claimed could lead to a breakthrough in fundamental physics while simultaneously improving high-precision ground-to-satellite navigation and redefining the second as a unit of time.

According to news reports, the Chinese researchers conducted the experiment in the western region of China involving two terminals in laboratories located about 70 km apart, with each terminal equipped with “a laser, a telescope, and two optical frequency combs” used for accurately measuring light frequencies. During the process, information was transmitted via laser pulses and into the two telescopes from each terminal, establishing and validating the time. The recent experiment demonstrated significant improvement over previous attempts, where laser-transmitted signals through the open air were limited to a few dozen kilometers, the lead quantum physicist Pan Jianwei from the University of Science and Technology of China (USTC) explained in a published peer-review journal on October 5. Moreover, adding that they aim “to be able to send signals over long distances to build a global network of optical clocks that would consequently play an integral role in enhancing satellite navigation services into more precise, more accurate ones.

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Using lasers to send signals through the open air comes with challenges, including wind turbulence and other atmospheric disturbances that cause signal loss. (Image source: CCTV)

Position, navigation, and timing (PNT) in navigation have become important features in recent years, especially in military activities with technological advances that keep growing—and the laser test is a potential sneak peek at what a future evolution of the Global Positioning System (GPS) would look like.

Ramping High-Precision Signals Using Optical Fibers

Chinese scientists previously used optical fibers, which carried high-precision signals up to a thousand kilometers. However, they could not stretch these cables between locations due to physical wire restrictions, opting to use open air instead.