The project FiBBS aims at the development of fibre‐based beam splitters for matter‐waves. We will investigate mode splitting of near‐infrared laser light in fibres, at wavelengths that are applicable for trapping ultra‐cold Caesium atoms in single and double‐well potentials. We will follow two approaches: first we will find a fibre that can simultaneously host a single and double mode at two different wavelengths and study how controlled we can blend from one mode to the other. In the second approach, we will attempt mode mixing in the fibre by inducing stress. Both approaches will be evaluated with respect to their feasibility to produce a beam‐splitter for matter waves, as used in trapped atom interferometry.