LFS4100
Chapter 6: Fusion Splicing
Rev B, July 24, 2018
Page 27
6.3. Fiber Alignment
WARNING
Similarly, the camera tower can generate a fair amount of force as it moves forward and back, and
up and down. It is strongly advised that users NOT put their fingers between it and the furnace or
mirror tower while the machine is in operation.
Before fusion, the two fibers to be spliced must be aligned by the edge, core, or end-view alignment methods
using the images captured by the camera tower or by the active alignment method. The edge and core alignment
methods use side view images to determine the positions of the fibers and align them in the XY plane. The end-
view alignment method uses images of the fiber ends to automatically control both XY and rotational position.
Alternatively, active alignment with an optical power meter can be used for fiber that has a high core eccentricity.
6.3.1. Edge Alignment
The edge alignment method aligns the edges of the fibers in the XY direction when the fibers are in front view and
back view position. To use this method, the fibers must first be set to the pre-gap distance. This gap allows
individual fiber movement and ensures proper identification of the fiber edges. The software then uses the image
data acquired by the CCD camera to precisely determine the location of the fibers. This positional information is
used to align the fibers by moving the stepper motor positioner. Successive images are analyzed and the fibers
are repositioned until they are aligned.
6.3.2. Core Alignment
The core alignment method is similar to the edge alignment method, except the system attempts to align the
cores of the fibers instead of the edges. This process can only be used where there is a clearly visible image of
the fiber cores. It is also essential that the core image is not distorted by the fiber claddings.
6.3.3. End-View Alignment (PM Alignment)
The end-view alignment method is used for polarization-maintaining fibers such as 3M elliptical-core fiber (PM or
PZ), Panda fiber, bow-tie style fiber, and for hybrid splices between any of these. These types of fiber require a
rotational alignment in addition to an XY alignment.
The end-view alignment process is initiated by using the “Lens Left or Lens Right” process. This instructs the
fibers to be pulled back so that a mirror can be inserted between the two fiber end faces. The image of the fiber
ends is then displayed and the automatic alignment can also take place. For the automatic alignment to be
successful, the PM alignment parameters must be correctly set to match each fiber type (as described below).
To make the LFS4100 perform PM alignment during a splice process, select the Alignment menu then select
Enable PM Alignment. Then, select PM to display the PM Alignment Configuration window. This window displays
two parameters for each fiber, as shown in Figure 17 below. The user must enter the correct fiber cladding
diameter, the fiber type, and the two PM geometry parameters for each fiber. If the fibers are the same, then
check the Same box. If the operator does not know the exact characteristics, it is possible to directly measure
them on screen.
Figure 17 PM Alignment Configuration Window
Summary of Contents for Vytran LFS4100
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