Fiber optic cable's flexibility stems from a combination of factors: the thinness of the glass fibers themselves, protective coatings, and specialized designs.
The Thin Glass Fibers
The core of a fiber optic cable is made of incredibly thin glass fibers. This inherent thinness contributes significantly to its flexibility. As noted in a Reddit discussion (https://www.reddit.com/r/explainlikeimfive/comments/ucgugf/eli5_how_is_it_that_the_glass_in_fiber_optic/), "The glass fibers are so thin that they're flexible." However, it's crucial to note there are limitations; bending them too sharply can cause damage.
Protective Coatings and Tensile Strength
The glass fibers aren't exposed. They are encased in protective layers. A buffer coating, typically made of acrylate or UV-cured urethane, surrounds the core and cladding ([reference from 04-Sept-2024]). This buffer not only protects the fragile glass but also contributes to the cable's overall flexibility. The tensile strength of these coatings further enhances flexibility and makes the cable easier to handle ([reference from 04-Sept-2024]).
Specialized Cable Designs
Manufacturers create different fiber optic cables for various applications. Some, like "Hi-Flex" or "Bend Insensitive" cables, are explicitly designed for greater flexibility (https://www.l-com.com/fiber-optic-bulk-bend-insensitive-hi-flex-singlemode-fiber-optic-cable, https://carriers.ustsubaki.com/en-int/products/cables-for-cable-carriers/foc-cables). These cables often incorporate design features that allow for tighter bending radii without compromising signal integrity. Examples include specialized coatings and fiber construction techniques.
Bend Radius Considerations
While fiber optic cables are flexible, they have a minimum bend radius. Exceeding this radius can damage the fibers. For single-mode fiber, the minimum bend radius is typically around 20mm, but it's always best to consult the manufacturer's specifications (https://thenetworkinstallers.com/blog/fiber-optic-cable-bend-radius/).
In summary, the flexibility of fiber optic cable is a result of the thin glass fibers, protective coatings that add tensile strength, and specialized designs in high-flexibility cables. However, care must be taken to avoid bending them too sharply.
