Block Free Optical Quantum Banyan Network based on Quantum State Fusion and Fission

TL;DR

This paper proposes a novel optical quantum switch design that uses quantum state fusion and fission to eliminate internal blocking in Banyan networks, enabling more efficient quantum communication.

Contribution

It introduces a practical scheme combining quantum state fusion, fission, and Fredkin gates to create block-free optical quantum switches based on Banyan networks.

Findings

Scheme successfully removes internal blocking in quantum Banyan networks

Conversion of quantum state fusion output mode enhances practicality

Design can be extended to more complex quantum switch units

Abstract

Optical switch fabric plays an important role in building multiple-user optical quantum communication networks. Owing to its self-routing property and low complexity, Banyan network is widely used for building switch fabric. While, there is no efficient way to remove internal blocking in Banyan network by classical way. Quantum state fusion, by which the two-dimensional internal quantum state of two photons could be combined into four-dimensional internal state of a single photon, makes it possible to solve this problem. In this paper, we convert the output mode of quantum state fusion from spatial-polarization mode to time-polarization mode. By combining modified quantum state fusion, quantum state fission with quantum Fredkin gate, we propose a practical scheme to build an optical quantum switch unit which is block free. The scheme can be extended to build more complex units, four of which are shown in this paper.