Abstract

LOPEZ GRANDE, Ignacio H  and  LAROTONDA, Miguel A. Active polarization stabilization in a single mode optical fiber link for quantum communications. An. AFA [online]. 2015, vol.26, n.4, pp.195-201. ISSN 0327-358X.

In this work we report the development of an active polarization stabilization loop of a single mode fiber optical link, based on two voltage-driven polarization controllers, and we study its performance. The goal is to obtain a polarization preserving channel for arbitrary polarization states, to establish a polarization-encoded quantum key distribution protocol. The system is able to generate four linear polarization states, corresponding to two conjugate linear bases: one of the basis corresponds to the polarization directions defined by an in-line polarizing beamsplitter placed at the end of the link, while the other corresponds to the conjugate (linear) basis. Following this initial operation, the system actively compensates for the birefringence changes of the channel that are mechanically and thermally induced by the environment, which have a detrimental effect on the initial bases election in temporal scales on the order of a few minutes. We show results of the system operating under the intense light regime using photodiodes in photoconductive mode, as well preliminary results in the photon counting regime.

Keywords : Active stabilization; Polarization; Optical fiber link; quantum key distribution.

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