refraction of the optical leads 11 and 17 is located between and surrounds the optical leads 11 and 17 the presence of the optical conducting substance 22 that matches the index of refraction of optical leads proximate the ends 11 a and 17 b reduces the optical reflections thereby providing an optical path from one optical lead 11 to the other optical lead 17 or vice versa with a minimum of back reflections thus a feature of coupler 10 is that the member 14 is rotatable with respect to member 13 without disrupting the optical path from optical lead 11 to optical lead 17 while at the same time inhibiting or reducing back reflections coupler 10 also includes a rotational alignment member or elongated key 19 which extends axially along member 14 positioned proximate to coupler 10 is an alignment sleeve 25 which is shown partially in section alignment sleeve 25 has a lumen therein for receiving flanged member 14 and an inner surface 25 a that mates with outer surface 14 b of member 14 to coaxially align member 14 within alignment sleeve 25 alignment sleeve 25 includes an alignment recess 25 b that extends in an axial direction from.