Distance increased by 100 million times! CSU achieves all-optical remote synchronization of two optical force systems

The ability to synchronize the motion of two oscillating objects has revolutionized technologies that require precise measurements to operate, such as clocks. For long-range coupling, researchers typically use electromechanical oscillators - whose motion is electrically driven and whose synchronization comes from an electronic coupling or physical connection. Now, Professor Chunhua Dong and his collaborators Changling Zou, from Academician Guangcan Guo's team at the Key Laboratory of Quantum Information, Chinese Academy of Sciences, University of Science and Technology of China, have optically synchronized the motion of two micron-sized objects separated by 5 km, a distance about 100 million times longer than previously demonstrated [1].

Chun-Hua Dong

This experiment demonstrated the motion of an oscillating microsphere and a vibrating microdisk through a 5-km, fiber-optic connection with optical coupling. Suggestion).

All-optical synchronization is achieved by injection locking (locking). (a) Illustration of two cascaded optomechanical systems driven by a monochromatic laser (connected by a single fiber); (b), (c) typical power spectral density of the second cavity in the unlocked and locked states.

(a) Schematic diagram of a long-range optical force synchronization device. fpc, fiber polarization controller; pd, photodetector; wdm, wavelength division multiplexing. (b) Typical optical mode transmission under thermo-optical and photo-mechanical effects when the pump laser scans the resonance of microsphere (top) and microdisk (bottom), respectively. (c), (b) The relevant mechanical frequencies during the scanning process of (c) and (d).

Synchronized results were achieved with two optical force systems separated by 12 meters of single-mode fiber.

(a) Schematic diagram of all-optical synchronization of different optical force regimes; (b) kinetic process of synchronization of a microsphere and a microdisk through a 5-km single-mode fiber; phase diagrams of two mechanical oscillators before (c) and after (d) synchronization.

The team fabricated a 38.7 µm diameter silicon sphere and a 41.76 µm diameter silicon disk that oscillate at the same resonant frequency, and then they connected these objects with a 5 km long coiled fiber.

To synchronize the motion of the objects, the spheres were first oscillated using the optical pressure of a high-power laser; after interacting with the spheres, the light was directed along the fiber to the disk to create a similar oscillation; measurements of the motion of the two objects showed that their vibrations were in phase.

Chunhua Dong said [1] that the technique allows for more robust synchronization of objects that are far apart because of the smaller loss of optical signals compared to electronic signals. "Optical coupling of mechanical oscillator motion has already been implemented in oscillators of integrated circuits. However, oscillators in pre-existing cases are only a few microns apart, which limits the application of the technique. The increased distance achieved in this experiment comes from a more detailed understanding of the optical synchronization of optical force systems, and the fine-tuning of the associated technology." The long-range all-optical synchronization technique demonstrated in this experiment lays the foundation for building complex networks of synchronized optical force systems, which are expected to have applications in fields such as optical communications and clock synchronization.

Jin Li, Zhonghao Zhou, a PhD student at CSU, and Shuai Wan, a postdoctoral fellow, are co-first authors of the paper, and Chunhua Dong and Ming Li are corresponding authors. The research work was supported by the National Key Research and Development Program, the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Collaborative Innovation Center for Quantum Information and Quantum Science and Technology Frontier [3].

Reference links:

[1]https://physics.aps.org/articles/v15/s109[2]https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.063605[3]http://news.ustc.edu.cn/info/1055/80037.htm