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Handling Fragile Optical Fibers and Fiber Pigtail Assemblies


Many fiber optic products incorporate fiber pigtail interfaces between the optical device and the optical connector. These fiber pigtails are extremely fragile and must be handled carefully to avoid breakage. Knots, kinks, twists and bends in the optical fiber will ruin the fiber's ability to transmit light. In many cases, a bend or break in an optical fiber will completely disrupt the system's performance. Dangling even an insubstantial weight from the end of a fiber can break or irreparably damage the fiber pigtail. This article outlines the proper procedure for handling these fragile optical fiber assemblies. Safe Fiber Assembly Handling
  1. Always read and comply with the handling instructions on the shipping container.
  2. Remember, optical fiber is made of glass. It should be treated with the same care.
  3. Never use the fiber to pick up or support the weight of the device to which it is attached. Instead, always keep both the device and the optical connector together in your hands.
  4. Do not allow kinks or knots to develop in the fiber. Carefully work out any tangles. Pulling on the fiber will cause any kinks or curls to tighten and exceed the minimum bend radius.
  5. Do not force the fiber into any retaining clips that may be used. First open the clips, slip the fiber carefully inside, and close the clips, making sure the fiber will not get caught in the clip latch.
  6. To remove pigtailed devices from the shipping container, use one hand to lift out the connector. Use the other hand to carefully uncoil the fiber. Once the fiber is uncoiled, carefully lift the fiber optic unit out of the shipping box. Do not dangle the box from the fiber as shown in Figure 1.

Figure 1 - Improper way to Handle Fragile Fiber Pigtails

Improper way to Handle Fragile Fiber Pigtails
Figure 2 - Letting the Fiber Dangle Over Sharp Corners will Damage the Fiber

Do not dangle fiber pigtails of the edge of table
Inserting the Optical Device into a Circuit Board
  1. Follow all integrated circuit standard insertion practices including ESD prevention measures.
  2. During insertion and soldering, take care not to place a thumb or heavy object on the fiber end of the device.
  3. A pigtailed device can be damaged easily if the fiber is touched by a hot solder iron. While this may not immediately break the fiber, it will increase loss due to local stresses, and it will compromise the physical strength of the fiber. A fiber damaged by a hot soldering iron is no longer a reliable device and should be replaced.
  4. After insertion, the fiber pigtail should be protected from damage.
  5. Never use the pigtail to support the weight of the circuit board.
  6. For best results, follow all ESD precautions and approved fiber cleaning procedures. For details on the proper fiber cleaning procedures, see article, "Fiber Optic Connectors."
  7. When securing the fiber to the PCB, do not use tight string, clamps or any mechanical mean to tightly bind the fiber. Local stress on the fiber increases loss and may break the fiber. Hard epoxies should also be avoided when securing fibers on a PCB. A pliable RTV is acceptable. Velcro® dots are by far the best way to secure fibers on a PCB. Visit http://www.velcro.com for more information.
  8. Be sure to secure fibers in units that include a ventilation fan so that the fiber does not get pulled into the fan.