Hermetically sealed optical fibre with voids or holes, method of its production, and its use

An optical fibre having an axial direction and a cross section perpendicular to the axial direction, the optical fibre having a first light guiding fibre portion with a cladding region with a plurality of spaced apart cladding voids extending longitudinally in the fibre axial direction and a core region bounded by the cladding region, and a solid light transparent fibre portion having a first end facing the first light guiding fibre portion and a second end forming an end face of the optical fibre. The solid light transparent fibre portion provides a hermetic sealing of the cladding voids of the first light guiding fibre portion. A method of producing such an optical fibre and its use, such as an optical fibre connector and an article having a microstructured optical fibre with hermetically sealed end face, are also included.