Fiber-optic realization of anisotropic depolarizing quantum channels

TL;DR

This paper presents a fiber-optic method to implement and characterize anisotropic depolarizing quantum channels for single-photon polarization states, enabling practical decoherence management in quantum communication.

Contribution

It introduces an electrically-driven polarization controller for depolarizing channels, characterized via quantum process tomography, compatible with fiber-optic systems and preserving photon modal structure.

Findings

Demonstrated a repeatable, low-cost depolarization method

Achieved accurate characterization using quantum process tomography

Ensured compatibility with fiber-optic quantum communication setups

Abstract

We employed an electrically-driven polarization controller to implement anisotropic depolarizing quantum channels for the polarization state of single photons. The channels were characterized by means of ancilla-assisted quantum process tomography using polarization-entangled photons generated in the process of spontaneous parametric down-conversion. The demonstrated depolarization method offers good repeatability, low cost, and compatibility with fiber-optic setups. It does not perturb the modal structure of single photons, and therefore can be used to verify experimentally protocols for managing decoherence effects based on multiphoton interference.