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We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters. Triggered by this conclusion, we investigate the 795.325 nm^{3} H_{6}↔^{3}H_{4} transition of Tm:Y_{3}Ga_{5}O_{12} (Tm:YGG). Most importantly, we find that the optical coherence time can reach 1.1 ms, and, using laser pulses, we demonstrate optical storage based on the atomic frequency comb protocol during up to 100 μs as well as a memory decay time T_{m} of 13.1 μs. Possibilities of how to narrow the gap between the measured value of T_{m} and its maximum of 275 μs are discussed. In addition, we demonstrate multiplexed storage, including with feed-forward selection, shifting and filtering of spectral modes, as well as quantum state storage using members of nonclassical photon pairs. Our results show the potential of Tm:YGG for creating multiplexed quantum memories with long optical storage times, and open the path to repeater-based quantum networks with high entanglement distribution rates.

Traditional methods for measurement of Polarizing Beamsplitter (PBS) parameters, especially the extinction ratio, require highly polarized light sources, alignment procedures and/or experimental parameters that change over time, such as polarization rotations. In this work, a new method is presented, which employs unpolarized light and a Faraday Mirror. It is shown that precise extinction ratio and insertion loss values can be achieved in three single-sweep measurements, without any alignment requirements or time-varying signals of any kind., Comment: 6 pages, 3 figures