Large Core Fiber Technology

A large core fiber is common fiber optic cable with a relatively large fiber core. Large core multimode fibers have a core diameter of 100 μm or even 400 μm which is really larger than the typical cables of 50 μm or 62.5 μm. A single-mode large core fiber also has a large effective mode area.

Here, the term large mode area fiber is more common and more appropriate, since the large mode area is a particularly important property: it results in reduced nonlinear effects combined with a high beam quality. You’ve probably seen this product type in high-end applications such as pools, fountains, or as accent lighting on the outside of buildings, strung on trees, lighted pathways for emergency routes, steps, refrigerated display cases, and a multitude of other applications.

Comparison of bare (uncoated) fibers with a standard large core size (e.g. 8 μm diameter) and a large core (50 μm diameter)

Pros and Cons Of Large Core Fiber

Large core fibers are flexible, but not as flexible as the same diameter made from small diameter fibers. When bent at sharp angles, large diameter fibers are less efficient, as they lose more light than small diameter fiber counterparts.

Large core fibers do a better job coupling light from large focal spot devices with the use of a single large core. There are physical limitations associated with traditional plastic and glass fibers, both must be made in small diameters to maintain flexibility. Therefore, these fibers are gathered in “bunches ” to make larger working diameters.

Large core end lit fiber works in same manner as traditional bulk fiber optic cable and offers some advantages over some traditional cables design.

In general, large core fiber advantages over traditional bulk fiber optic cable
1. Can be field applied and installed by almost anyone. (no grinding or polishing is required; but the “cleave” should be uniform and perpendicular to the body of the fiber)
2. More light is transmitted (within equivalent areas).
3. Better color rendering – more light stays in the fiber for longer distances, making the light output look “whiter” or “brighter”.
4. Approximate the look of neon without the cost.
5. Higher temperature resistance than PMMA (Plastic acrylic) fiber (100C vs 70C).
6. Available in side emitting type.
7. Reduced transmission of IR energy – less heat is transferred (No filters required).

More prone to deterioration from UV sources.
Exposure to water/moisture will corrode the core, special jacketing is required for outdoor use.
Prone to chemical metamorphosis within the core, the material becomes less flexible over time.

End face preparation of large core optical fiber is essential to obtain best transmission performance, particularly when high optical power is injected into the fiber. The best transparency is obtained by cleaving the fiber as opposed to polishing where small scratches always remain.

Recommend you to buy fiber optic cable from FiberStore who markets an extensive line of large core fibers. The product is easily adapted to outdoor applications.