Overview

This brief chapter contains rules relating to the art of spicing and connecting fibers. Providing a termination to a fiber and properly getting the light into the next fiber may seem trivial, but it is of utmost importance. A fiber cable must be spliced every 10 km or so, simply because trucks can't hold spools that hold more. (Underwater cables are spliced every few hundred kilometers, as ships can hold larger reels.) Connects are required at every EDFA and switch, and a packet may traverse numerous connectors at each Telecom hotel. The slightest bit of back-reflection or loss can add up over this link to cause intermittent and permanent failures.

Generally, connector refers to a fiber termination that allows the fibers to be connected and disconnected multiple times. On the other hand, a splice is a "fusion" or "weld" used to form the connection, and it is meant to be permanent and never disconnected.

The quality of splices and connections can be affected by tolerances on the lateral misalignment of the fibers, angular misalignment, gap lengths, mismatched numerical apertures, residual contamination, and mode mismatch. Also affecting the quality are the tolerances on the fiber geometry itself such as the ovality, curl, diameter, and core/clad concentricity of the fiber. When making a splice or installing a connector, the fatigue of the human and, if outdoors, even wind can play a role in performance, as it can cause vibration in the splicing equipment.

The primary concerns for a splice...