Quantum encoder and decoder for practical quantum key distribution using a planar lightwave circuit

• Published in: Journal of modern optics Vol. 55; no. 12; pp. 1953 - 1970
• Main Authors: Nambu, Yoshihiro, Yoshino, Ken'ichiro, Tomita, Akihisa
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01-07-2008; Taylor & Francis
• Subjects: Classical and quantum physics: mechanics and fields; Exact sciences and technology; Physics; Quantum communication; quantum encoder and decoder; Quantum information; quantum key distribution; Optical fibers; Mach-Zehnder interferometers; Optical polarization; Optical communication; Optical fiber communication; Quantum information; Quantum key distribution; Planar device; Reliability; Quantum communication; Photonics
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500340801942414

To launch quantum key distribution (QKD) into the commercial market, it is important to develop a system that is simpler and more reliable using current technology. This report proposes quantum encoders and decoders using a passive planar lightwave circuit (PLC) that is useful for implementing optical-fiber-based QKD systems. Our encoders and decoders are based on an asymmetric Mach-Zehnder interferometer and allow us to prepare and analyze various photonic time-bin qubits reliably. The system can be stable and polarization-insensitive merely by stabilizing and controlling the device temperature. Our PLC-based devices enables us to simplify the QKD system and increase its reliability.