Suppression of polarization decoherence for traveling light pulses via bang-bang dynamical decoupling

TL;DR

This paper demonstrates that bang-bang dynamical decoupling, implemented with waveplates, can effectively suppress polarization decoherence in optical pulses traveling through dispersive media, enhancing quantum communication fidelity.

Contribution

It provides an experimental proof of principle for using bang-bang control to protect polarization qubits during propagation in dispersive optical fibers.

Findings

Bang-bang control reduces polarization decoherence in optical fibers.

Waveplates can implement effective dynamical decoupling operations.

Potential for improving quantum communication robustness.

Abstract

In the propagation of optical pulses through dispersive media, the frequency degree of freedom acts as an effective decohering environment on the polarization state of the pulse. Here we discuss the application of open-loop dynamical-decoupling techniques for suppressing such a polarization decoherence in one-way communication channels. We describe in detail the experimental proof of principle of the "bang-bang" protection technique recently applied to flying qubits in [Damodarakurup et al., Phys. Rev. Lett. 103, 040502]. Bang-bang operations are implemented through appropriately oriented waveplates and dynamical decoupling is shown to be potentially useful to contrast a generic decoherence acting on polarization qubits propagating in dispersive media like, e.g., optical fibers.