Ultrafast laser ablation of a multicore polymer optical fiber for multipoint light emission

We demonstrate the use of ultrafast laser pulses to precisely ablate the side of polymer multicore optical fibres (MCF) in such a way that light is efficiently coupled out of a set of MCF cores to free space. By individually exciting sets of MCF cores, this flexible "micro-window" technology allows the controllable generation of light sources at multiple independently selectable locations along the MCF. We found that the maximum fraction of light that could be side coupled from the MCF varied between 55% and 73%.