Light transfer control and diffraction management in circular fibre waveguide arrays

Discrete diffraction management and control of light transfer via evanescent coupling in a circular array of twisted optical fibres is theoretically demonstrated. In particular, it is shown that fibre twist can be exploited to cancel discrete diffraction, to tune the coupling length in a simple two-fibre directional coupler and to control the optical tunnelling between two communicating defects in the array. Quantum-optical analogues of the proposed schemes for the control of discretized light in the array are also elucidated.