Abstract:In this paper we present the fabrication of optical mode field adaptors for fiber optical communications using fiber splicing machine in special newly developed modus. We developed mode field transformers with radii from 5 m to 80 m the end of standard singlemode and multimode glass fibers, characterized by far field and near field methods. Easy and reliable fabrication of the radii with low standard deviation = 0.16-0.97 m or better than 3,2% relative to the mean radius has been achieved.