Competence Center for Specialty Optical Fibers

In this Letter, we present, to the best of our knowledge, the largest effective single-mode fiber reported to date. The employed waveguide is a passive large pitch fiber (LPF), which 02.01.2019shows the core area scaling potential of such a fiber structure. In particular, we achieved stable singletransverse mode transmission at a wavelength of 1.03 μm through a straight passive LPF with a pitch of 140 μm, resulting in a measured mode-field diameter of 205 μm.