@article{oai:ynu.repo.nii.ac.jp:00009297,
 author = {Niizeki, Kazuya and Ikeda, Kohei and Zheng, Mingyang and Xie, Xiuping and Okamura, Kotaro and Takei, Nobuyuki and Namekata, Naoto and Inoue, Shuichiro and Kosaka, Hideo and Horikiri, Tomoyuki},
 journal = {Applied physics Express},
 month = {Mar},
 note = {We demonstrate an ultrabright narrow-band two-photon source at the 1.5μm telecom wavelength for long-distance quantum communication. By utilizing a bow-tie cavity, we obtain a cavity enhancement factor of 4.06 ' 104. Our measurement of the second-order correlation function G(2)(τ) reveals that the linewidth of 2.4MHz has been hitherto unachieved in the 1.5μm telecom band. This two-photon source is useful for obtaining a high absorption probability close to unity by quantum memories set inside quantum repeater nodes. Furthermore, to the best of our knowledge, the observed spectral brightness of 3.94 ' 105 pairs/(s&MHz&mW) is also the highest reported over all wavelengths.},
 pages = {042801-1--042801-5},
 title = {Ultrabright narrow‐band telecom two‐photon source for long‐distance quantum communication},
 volume = {11},
 year = {2018}
}