瞬态光学研究室知识库

In this paper, we demonstrate a cascaded transfer of optical frequency with a relay station over a fiber link. The station is outfitted to cascade numerous lines with independent phase locking and provide high optical gain. The relay station receives the signal from the former link and compensates for the power loss with a two-stage EDFA (erbium-doped fiber amplification), and seeds the amplified signal into the next fiber link. By actively suppressing the parasitic noise with a two-stage EDFA, low-noise optical amplification with 50 dB gain is achieved. The two-stage EDFA's simple phase-locking structure also guarantees the system's long-term stability and reliable operation. With this relay station, we transfer a laser frequency along with a 224 km deployed fiber link, and the frequency at the remote end achieves a fractional instability of 3.39 x 10-16 at 1 s averaging time on a 2 Hz measurement bandwidth, reaching 8.36 x 10-19 at 10,000 s. This work paves a way for the future fiber optical frequency transfer network across the nationwide area and it has the potential to be an important part of the cascaded transfer network.