SD-44
SD44 Optical-to-electrical Converter
From Tektronix' site:
The SD44 is an optical-to-electrical (O/E) converter for use with the Tektronix CSA803 and 11800 Series sampling oscilloscopes equipped with an SD2x or SD3x Electrical Sampling Head. The SD44 Optical-to-electrical Converter can be plugged directly into a 11800 sampling slot, CSA803 power slot, or attached via a sampling head extender cable for remote use. The head extenders come in either 1 meter (012-1220-00) or 2 meter (012-1221-00) options.
Optical signal input on the SD44 is a standard FC/PC fiber optic connector. Other connector types can be accommodated by using hybrid fiber optic jumper cables (SA/SD42) or an assortment of hybrid mating adapters (SD44).