Optical coherence transfer over 50-km spooled fiber with frequency instability of 2×10<sup>−17</sup> at 1 s

Optical coherence transfer over 50-km spooled fiber with frequency instability of 2×10⁻¹⁷ at 1 s

Ma Chao-Qun, Li-Fei Wu, Jiang Yan-Yi†, Yu Hong-Fu, Bi Zhi-Yi, Ma Long-Sheng

Schematic setup for optical frequency transfer. Fiber-induced phase noise is detected on PD₁, and is compensated by controlling the frequency of AOM₁. The performance of fiber noise compensation is tested on PD₂ by comparing the fiber-transferred light with the original laser light. PD, photo detector; P, polarizer; FFT, fast Fourier transformer; PBS, polarization beam splitter; FM, Faraday mirror; DBM, double balanced mixer. All the optics except the 50-km spooled fiber and AOM₂ are placed in an acrylic box and all the connectors for cables and fibers are installed in the box.