For installed spans, linking the OTDR to the span under test requires a hybrid patch cord.
Most OTDRs have an internal ultra physical contact (UPC) spherical polish,
but some reflection-sensitive systems use the angled physical contact (APC) polish.
There are two methods of terminating a fiber.
The first method uses a bare-fiber adapter, whichconsists of a plug body that grips the fiber to be
tested. The design of the bare-fiber adapter is such that the fiber can pass completely through the
adapter body and damage the optical port. Because of this, the barefiber adapter must never be
connected directly to the OTDR.Instead, the adapter should be used with a short patch cord and mating
adapter sleeve to isolate damage from the OTDR’s port.
The second method uses a pigtail with a reusable mechanical splice, which allows easy mating of
the fibers to be tested with the OTDR. The Norland reusable mechanical splice has been used for
decades for testing bare fibers.
It features a glass body that internally holds and aligns two fibers.
The splice is filledwith a refractive index matching fluid to reduce reflections.
To make the connection, strip and cleave both of the fibers to be tested,
then insert and center both into the mechanical splice to complete the termination.