Optical Frequency Transfer on the Order of 10−19 Fractional Frequency Instability over a 64 m Free-Space Link

Autor: Guoyong Wang, Zhangjian Lu, Xinwen Liang, Keliang He, Yuling He, Xin Ji
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Photonics, Vol 11, Iss 7, p 587 (2024)
Druh dokumentu: article
ISSN: 11070587
2304-6732
DOI: 10.3390/photonics11070587
Popis: High-precision time–frequency is widely used in time measurement, satellite navigation, scientific research, and other fields. With the rapid development of optical clock technology, the fractional frequency instability and uncertainty of optical clock have reached 10−18 orders of magnitude, which is expected to contribute to generating the International Atomic Time and may even be used to redefine the “second” in the future. Therefore, the long-distance transfer of time–frequency signals between optical atomic clocks is of great significance. Free-space optical frequency transfer technology is one of the important technologies for solving the space-based optical clock comparison because of its high transfer precision and easy networking characteristics. In order to solve the long-distance space-based optical clock comparison, this paper investigates a free-space active phase noise compensation method using an Acousto-Optic Modulator (AOM), based on the traditional optical fiber phase noise compensation scheme. This new method is more flexible and scalable than the optical fiber time–frequency transfer technology. The optical frequency transfer over a 64 m free-space link is demonstrated. The fractional frequency transfer instability during free running is 9.50 × 10−16 at 1 s, and 4.44 × 10−16 at 2000 s, and the fractional frequency instability after compensation is 7.10 × 10−17 at 1 s, 3.07 × 10−19 at 2000 s, which is about 1–3 orders of magnitude better than that in free running, and provides a feasible scheme for space-based optical clock comparison.
Databáze: Directory of Open Access Journals
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