Several experimental realizations of symmetric phase-covariant quantum cloner of single-photon qubits

TL;DR

This paper compares various optical implementations of symmetric phase-covariant quantum cloning machines for single-photon qubits, highlighting their advantages and disadvantages through experimental realizations.

Contribution

It provides a comparative analysis of multiple experimental setups for phase-covariant quantum cloning, including bulk optics and fiber-based methods.

Findings

Different implementations have unique advantages and disadvantages.

All setups successfully perform phase-covariant cloning.

Fiber-based setup allows encoding in spatial modes.

Abstract

We compare several optical implementations of phase-covariant cloning machines. The experiments are based on copying of the polarization state of a single photon in bulk optics by special unbalanced beam splitter or by balanced beam splitter accompanied by a state filtering. Also the all-fiber based setup is discussed, where the information is encoded into spatial modes, i.e., the photon can propagate through two optical fibers. Each of the four implementations possesses some advantages and disadvantages that are discussed.