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Sagnac secret sharing over telecom fiber networks
Jan Bogdanski1, Johan Ahrens, Mohamed Bourennane
1Department of Physics, Stockholm University, S-10961 Stockholm, Sweden. janbog@physto.se
Optics Express
|January 23, 2009
Summary
This study demonstrates practical quantum secret sharing using a single qubit protocol over fiber optic networks. The novel Sagnac configuration achieves stable, long-distance quantum communication, overcoming previous scalability and implementation challenges.
Area of Science:
- Quantum Information Science
- Quantum Communication
- Quantum Cryptography
Background:
- Previous quantum secret sharing (QSS) proposals relied on complex multiparticle entangled states, hindering practical implementation and scalability.
- Implementing QSS over existing fiber optic infrastructure presents challenges due to signal degradation and environmental factors like birefringence.
Purpose of the Study:
- To demonstrate the first Sagnac quantum secret sharing (QSS) implementation using a single qubit protocol over 1550 nm single mode fiber (SMF) networks.
- To develop and validate a stable QSS system capable of overcoming birefringence effects in standard telecom fiber channels.
- To assess the feasibility of practical QSS for multi-party scenarios in fiber optic networks.
Main Methods:
- Utilized a single qubit protocol with phase encoding for quantum secret sharing.
- Implemented a Sagnac interferometer configuration for stable quantum transmission over SMF.
- Developed a novel birefringence compensation technique using a polarization control system and a polarization-insensitive phase modulator.
Main Results:
- Achieved stable quantum secret sharing transmissions over 55-75 km in three-party setups and 45-55 km in four-party setups.
- Reported Quantum Bit Error Rates (QBER) between 1.7-3.7% depending on photon number and party configuration.
- Demonstrated stable quantum transmission by effectively compensating for SMF birefringence effects.
Conclusions:
- The single qubit Sagnac QSS protocol is feasible for practical implementation over standard telecom fiber networks.
- The developed birefringence compensation method ensures stable quantum transmissions, overcoming a major hurdle for fiber-based QSS.
- This work paves the way for secure quantum communication solutions utilizing existing fiber optic infrastructure.
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