Ion beam implantation for fabrication of periodic structures in optical fibres

Abstract

Ion beam implantation using 2.4 MeV H+ ions was used to fabricate long period gratings in multimode optical fibres. The Bragg peak from the ion beam was located in the centre of the core of the fiber. The ion beam was implanted through a mask on the fibre with a period of 1.1 mm to produce a periodic a refractive index modulation, of up to 1%, along the axis of the core of the fibre. The mode scrambling, from the established fundamental mode, was monitored in situ as the implantation was done by observation of the light transmitted through the fibre. This paper describes the experimental method used to achieve this and describes the results. Significant mode scrambling was observed to occur ..