Quantum Communication Experiments Over Optical Fiber
Quantum key distribution (QKD) is expected to be the first application of quantum information to be realized as a practical system. In the last decade, research on QKD made significant progress both in concept and technology. In this chapter, we review the progress of technologies designed to realize high-speed and long-distance quantum communication over optical fiber, focusing on the results obtained by NTT. The first section describes a roadmap towards scalable quantum communications, which is composed of three phases. The second section reviews our effort to realize phase 1 quantum communication systems, namely point-to-point QKD systems based on the differential phase shift QKD (DPS-QKD) protocol. The third section describes entanglement generation and application in the telecom band, which are the key technologies for realizing phase 2 and 3 systems. The final section provides a summary and describes the future outlook.
KeywordsQuantum communication Quantum key distribution Entanglement Optical fiber
The work described here is the result of collaborations with many researchers. I would like to thank all my collaborators, in particular Prof. Kyo Inoue (Osaka University) and Dr. Toshimori Honjo (NTT Laboratories).
- 2.C.H. Bennett, G. Brassard, Quantum cryptography: public key distribution and coin tossing, in Proceedings of IEEE International Conference on Computers, Systems and Signal Processing, Bangalore, (1984), pp. 175–179Google Scholar
- 31.H. Takesue, K. Inoue, Generation of polarization entangled photon pairs and violation of Bell’s inequality using spontaneous four-wave mixing in fiber loop. Phys. Rev. A 70, 031802(R) (2004)Google Scholar
- 32.H. Takesue, K. Inoue, Generation of 1.5-μm band time-bin entanglement using spontaneous fiber four-wave mixing and planar lightwave circuit interferometers. Phys. Rev. A 72, 041804(R) (2005)Google Scholar
- 40.M. Koashi, Y. Adachi, T. Yamamoto, N. Imoto, Security of entanglement-based quantum key distribution with practical detectors. arXiv:0804.0891 (2008)Google Scholar
- 41.T. Honjo, S.W. Nam, H. Takesue, Q. Zhang, H. Kamada, Y. Nishida, O. Tadanaga, M. Asobe, B. Baek, R Hadfield, S. Miki, M. Fujiwara, M. Sasaki, Z. Wang, K. Inoue, Y. Yamamoto, Long-distance entanglement-based quantum key distribution over optical fiber. Opt. Express 16, 19118–19126 (2008)Google Scholar
- 45.H. Takesue, K. Inoue, 1.5-μm band quantum-correlated photon pair generation in dispersion-shifted fiber: suppression of noise photons by cooling fiber. Opt. Express 13, 7832–7839 (2005)Google Scholar
- 61.S. Mino, H. Yamazaki, T. Goh, T. Yamada, Multilevel optical modulator utilizing PLC-LiNbO3 hybrid-integration technology. NTT Tech. Rev. 9(3), (2011). https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr201103fa8.pdf&mode=show_pdf