TABLE OF CONTENTS A fiber splice is a permanent or temporary low-loss bond between two fibers. Such a bond can be made by using either fusion splicing or mechanical splicing. Most splices are permanent and typically are used to create long optical links or in situations where frequent connection and disconnection is not needed. Temporary splices may be necessary or convenient when one is making emergency cable repairs or doing testing during installation or troubleshooting. Here we will first look at general splicing issues and then examine fusion and mechanical splicing methods.
In making and evaluating optical fiber splices, one must take into account the physical differences in the two fibers, fiber misalignments at the joint, and the mechanical strength of the splice.
The physical differences in fibers that lead to splice losses are the same as those discussed above for connectors and result in what is called intrinsic loss. These fiber-related differences include variations in core diameter, core-area ellipticity, numerical aperture, and core-cladding concentricity of each fiber. Extrinsic losses depend on how well the fibers are prepared and the care taken to make the splice. The factors here include fiber misalignments at the joint, the smoothness and cleanliness of the fiber end faces, and the skill of the splice equipment operator. When the fiber bonding is done properly using high-quality equipment, the total splice loss typically is 0.05 to 0.10 dB for fusion splicing and around 0.5 dB for mechanical splices.
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