Quantum propagation in optical fibres

P. D. Drummond, Robert M. Shelby, Stephen R. Friberg +1 more

Keith J. Blow, R. Loudon, Simon J. D. Phoenix

Quantum theory, as normally formulated, describes systems enclosed in an artificial box through its time evolution. In some systems, such as a laser, the box may be a physical element such as a cavity. In optical fibre communications the situation is somewhat different. The optical field is continuously generated by a source such as a laser. Once generated the field propagates along an optical fibre and is detected in some form of receiver at the far end. Quantum theory, with its reliance on Hamiltonian systems necessarily conserves the total energy in the system whereas fibre communication is better described as a balance between sources and sinks. Under these circumstances it may be more appropriate to describe the spatial evolution of the field [1], [2], [3]. In this paper we describe an approach to the study of quantum propagation in optical fibres. The discussion will be based on the description of single mode weakly guiding fibres so that a one dimensional scalar wave equation can be used to describe the electric field.

M. A. Sagioro, Sebastião Pádua

We theoretically demonstrate a new scheme for cancelling the dispersive effects in quantum communication with two entangled photons propagating in optical fibres. In the case of two entangled photons generated by spontaneous parametric down-conversion and propagating in two optical fibres, it is demonstrated that the dispersive effect in the biphoton wavepacket is cancelled by inserting only one Fabry–Perot cavity into one of the fibre's lines. No special dispersive material or interference of the transmitted photons in a beam splitter (or interferometer) is necessary. In the scheme, where one of the photons is reflected by the Fabry–Perot cavity before being transmitted by the fibre, a full dispersion cancellation is shown with no decrease in the number of photons at the optical fibres exit.

K. J. Blow, R. Loudon, Simon J. D. Phoenix

Natalia Korolkova, Gerd Leuchs, Stefan Schmitt +5 more

GUILHERME BARRETO XAVIER, G. Lima

Abstract The optical fibre is an essential tool for our communication infrastructure since it is the main transmission channel for optical communications. The latest major advance in optical fibre technology is space-division multiplexing, where new fibre designs and components establish multiple co-existing data channels based on light propagation over distinct transverse optical modes. Simultaneously, there have been many recent developments in the field of quantum information processing, with novel protocols and devices in areas such as computing and communication. Here, we review recent results in quantum information based on space-division multiplexing optical fibres, and discuss new possibilities based on this technology.