Rare-earth ions doped in solid-state materials are considered promising candidates for quantum information applications, especially for photonic quantum memory. Among them, erbium ions doped in an optical fiber have attracted a lot of attentions due to their ability to provide efficient photon-atom interaction on a telecom-C band compatible transition. The coherent photon-atom interaction, which is crucial for quantum memory, has not yet been investigated for erbium ions doped in fiber at the temperature of sub 10 mK with the magnetic environment. In this paper, we experimentally observe optical nutation, which results from the coherent interaction between laser and erbium ions ensemble, in a piece of 9.5-m-long fiber with the erbium concentration of 200 ppm. We also extract the transition dipole moment from the results of optical nutation and further investigate its dependence on laser wavelength and magnetic field. A transition dipole moment of (3.424±0.019)×10⁻³² C·m is obtained at the wavelength of 1537 nm and magnetic field of 0.2 T. Our results could pave the way for realizing solid-state quantum networks at telecom-C band.

掺杂在固态材料中的稀土离子被认为是量子信息应用（尤其是光子量子存储）中有希望的候选者。其中，掺杂在光纤中的离子由于能够在电信-C波段兼容的过渡上提供有效的光子-原子相互作用而备受关注。对于量子存储至关重要的相干光子-原子相互作用，还没有研究在磁性环境下在低于10 mK的温度下掺杂在光纤中的ions离子。在本文中，我们通过实验观察到光学nut合现象，这是由于在and浓度为200 ppm的9.5米长光纤中，激光与laser离子整体之间的相干相互作用而产生的。我们还从光学章合的结果中提取跃迁偶极矩，并进一步研究其对激光波长和磁场的依赖性。跃迁偶极矩为（3.424±0.019）×10在1537 nm的波长和0.2 T的磁场下获得⁻³² C·m。我们的结果可为在电信C波段实现固态量子网络铺平道路。