... , low PDL High directivity, high return loss All-optical structure 2x2 optical coupler SM, single window 1310 or 1550 + / ... -20nm Standard-NC (tube) Tree structure Stainless steel tube 2x2 optical coupler, SM, single window, standard-NC (tube), 9/ ... PDL. High directivity, high return loss. All-optical structure. Stainless steel sleeve.Electrical Performance Item UnitSpecificationStandardWavelength ...