Continuous variable quantum secret sharing using directly modulated lasers

Abstract

Quantum secret sharing (QSS) allows multiple players to achieve unconditional secure communication through an unsecure quantum channel; however, the actual implementation requires a modulator with a high extinction ratio, which means high system expense and miniaturization and commercialization difficulties. In this paper, we propose a continuous variable QSS scheme that can replace the traditional lasers and modulators with directly modulated lasers (DML). Each player prepares quantum states through a DML and sends the signal light to the dealer through a beam splitter into a quantum channel. The method provides a new way for realizing secret key sharing. Moreover, we introduce the chirp estimation algorithm to realize the phase modulation, which can achieve a two-dimensional modulation scheme under a single laser.