Eur. Phys. J. D (2012) 66: 42
https://doi.org/10.1140/epjd/e2011-20451-2

Regular Article

Quantum channel with controllable decoherence using polarization-time coupling

¹ Center for Telecommunication Studies, Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rua Marquês de São Vicente 225, 22451-900 Rio de Janeiro, Brazil
² Departamento de Ingeniería Electrica, Universidad de Concepción, 160-C Casilla, Concepción, Chile
³ Center for Optics and Photonics, Universidad de Concepción, 4016 Casilla, Concepción, Chile

^a e-mail: temporao@opto.cetuc.puc-rio.br

Received: 3 August 2011
Received in final form: 5 December 2011
Published online: 24 February 2012

Abstract

An optical quantum channel that introduces decoherence in the polarization state by continuously controlling the output degree of polarization (DOP) is proposed, and a proof-of-principle experiment is performed. The decoherence is achieved by a depolarizing process that couples the polarization and time-of-flight degrees of freedom of the single photons in a high-birefringence medium, and is experimentally characterized via standard quantum state tomography. It is shown that the output DOP is independent of the input polarization state and the response times of the photodetectors.