All-optical quantum switching

B. C. Jacobs, T. B. Pittman, J. D. Franson

Han Ji-qu

In order to study system of quantum communication, a scheme of quantum switch based on optical switch is presented, which is the node of quantum communication network. The quantum switch is mainly made up of optical crossing module, switch controller module and in-out module. It builds the photon link between sender and receiver of quantum communication network, and provides quantum channel for transferring quantum information between them. The experiment bed of this quantum switch is established, and the test result with weak optical resource indicates that this quantum switch can be used for quantum communication network and can also realize the function of quantum communication network.

Warit Asavanant, Kosuke Fukui, A. Sakaguchi +1 more

Optical switches and rerouting networks are considered essential in optical quantum computers where they are used for injection and dejection of the necessary quantum states into an optical quantum computer. Practical optical switches and rerouting networks are, however, experimentally challenging as they must have extremely low loss, small switching time, high repetition rate, and minimum optical nonlinearity, requirements that are difficult to achieve simultaneously. In this paper, we present an optical quantum computation platform that does not require such optical switches. Our method is based on continuous-variable measurement-based quantum computation where, instead of the typical cluster states, we modify the structure of the quantum entanglement, so that the quantum teleportation protocol can be employed instead of optical switching and rerouting. The quantum entanglement structure in our architecture has additional modes that allow quantum states to be teleported in or out of the computation along the cluster state, a task that normally requires optical switches. We also outline how to combine our platform with Gottesman-Kitaev-Preskill encoding, the currently most promising encoding for a continuous-variable system.

Thomas Volz, Andreas Reinhard, Martin Winger +4 more

Gregory S. Kanter, M. S. Shahriar

Abstract : All-optical switching is crucial for efficient optical communications. The quantum Zeno effect can be used to induce or inhibit optical switching through a variety of processes, all of which share the common characteristic that the evolution of one quantum state into another be inhibited or induced based on the presence or absence of a controllable and continuous quantum measurement. By utilizing this effect, it is the goal of this project to design and construct ultra-low power dissipation, ultra-low volume, fast all-optical switches. In particular, a fundamental limit in existing all-optical switching devices is due to the photon loss resulting from signal-pump coupling. When extended to the quantum domain, this photon loss additionally causes the quantum states of photonic signals to collapse (i.e., decohere). By using the quantum Zeno effect (QZE), it is possible to realize interaction-free switching that eliminates direct signal-pump coupling i.e., QZE for all-optical switching.