Grinderslev, S., "Fiber Optic Expanded Beam Size 16 Termini," SAE Int. J. Aerosp. 5(1):206-213, 2012, doi:10.4271/2012-01-2128.
For most data and telecom fiber optic applications the physical contact (PC) concept is preferred for all indoor and even some outdoor applications. But when these connectors are subjected to a harsh environment, the performance of standard PC connectors has proven unreliable in many applications due to their sensitivity to contamination. The subject for this paper is the design of a small form factor expanded beam (EB) fiber optic contact pair suited for operation in a challenging environment. The contacts conform to the dimensional envelope of MIL-PRF-29504/4/5D and employ a separable lens unit design which provides the option for field-installable terminations. The EB concept typically exhibits a higher loss than the PC connection, but preliminary results of the new design indicate that the size 16 termini pair using 1.25mm lenses and ferrules yields a very good loss performance.