Experimental Demonstration of Robust Bidirectional Quantum Optical Communications

TL;DR

This paper demonstrates a practical method for bidirectional quantum communication over optical fibers using interference techniques to cancel noise, enhancing the reliability of quantum information transfer.

Contribution

It introduces an improved, bidirectional quantum communication setup utilizing interference in polarization-maintaining fibers, extending decoherence-free subspace methods.

Findings

Successful experimental realization of bidirectional quantum communication.

Quantitative analysis confirms robustness against noise.

Potential for practical quantum communication applications.

Abstract

We experimentally realized a new method for transmitting quantum information reliably through paired optical polarization-maintaining (PM) fibers. The physical setup extends the use of a Mach-Zehnder interferometer, where noises are canceled through interference. This method can be viewed as an improved version of the current decohernce-free subspace (DFS) approach in fiber optics. Furthermore, the setup can be applied bidirectionally, which means that robust quantum communication can be achieved from both ends. To rigorously quantify the amount of quantum information transferred, optical fibers are analyzed with the tools developed in quantum communication theory. These results not only suggests a practical means for protecting classical and quantum information through optical fibers, but also provides a new physical platform for enriching the structure of the quantum communication theory.