Fiber Optics - Connecting fiber optics - splicing

What is Fiber optics?

Fiber optics is a glass fiber which is used to carry signals in the form of pulses of light over distances up to 50 km without the need for repeaters. The term optical fibers indicate special forms of optical waveguides, the most important special features of which are:

  • rotationally symmetrical cross-section

  • Flexible

  • can be produced in great lengths

The characteristics of optical fibers are determined by a multitude of possible constructive details.

What is Splicing?

The splice is a method of joining two fibers properly aligned so that the two fibers are held together and the transmission of light continues. There are two kinds of permanent joints in fiber optics:

  • Fusion splicing

  • Mechanical splicing

The generally accepted splicing method is arc fusion splicing, which melts the fiber ends together with an electric arc. For quicker fastening jobs, a “mechanical splice” is used.

Fusion splicing:

Fusion splicing is used for good quality permanent joint welding, A heating source widely used for fusion is the electric arc. The prepared fiber ends are placed in a precision alignment template. The alignment is made with the help of an inspection microscope.

A short arc discharge is applied to fire polish the fiber ends. This removes any defects due to imperfect cleaving. In the final step, the two ends are pressed together and fused with a stronger arc, thus producing a fusion splice.

Mechanical splicing:

There are several mechanical techniques of splicing fibers. These normally use appropriate fixtures for aligning the fibers and holding them together. There are different type of mechanical splicing:

Glass alignment tube:

The prepared fiber ends are gently inserted into the capillary and a transparent adhesive is injected through a transverse hole. The adhesive guarantees both mechanical bonding and index matching. In this way a stable low loss junction can be obtained, but it has strict limits in the capillary diameters.



The simplest technique uses an open V-groove, in which the prepared fiber ends are placed. The splicing is carried out with the help of epoxy resin. It is also possible to obtain a suitable slot by placing two precision pins close to each other. The fibers can be placed on the cusp and the transparent adhesive ensures the joint, as well as the coincidence of indexes, and a flat spring at the top applies pressure to ensure that the fibers remain in their positions. Such a groove is called a spring groove.