DESCRIZIONE
An illuminator comprising a side emitting optical fiber or bundle of side emitting optical fibers and an optical device comprising a sealed / closed housing; a light source and/or a detector within the housing; a window through the housing that is transparent to light transmitted from the light source or to the detector; and a fixing for fixing the side emitting optical fibre or side emitting optical fiber bundle into a coupling position adjacent to the window to allow light to pass between the housing and the fibre or fibre bundle, wherein the fixing is adapted to allow connection and/or disconnection of the fibre or fibre bundle without opening or breaking a seal of the sealed housing. [Image Omitted]