G PHYSICS
G02 OPTICS
G02B OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
G02B6/24 Coupling light guides
G02B6/26 Optical coupling means
G02B6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting
G02B6/266 the optical element being an attenuator