FIBERCORE SM600 Single Mode Fiber for 633nm and 688nm. This fiber has 4.3m core, 125m cladding and 245m coating. With single mode transmission characteristics well matched to HeNe laser at 633nm, Diode Laser at 680nm.Singlemode transmission at all common Visible and NIR source wavelengths125m glass diameter enables the use of standard ferrules, vgrooves and connectorsTypical 0.11 0.13 NA gives good resistance to bend induced loss without creating an unmanageably small mode.FIBERCORE Single Mode Fibers Spec Sheet: SMF600 Spec Sheet