Bend Radius—How It Can Impact Your Cable Performance?

Why should fiber optic cable not be tightly bent? Are fiber optic cable fragile? These issues are what users care about when deploying fiber patch cables. Usually, fiber optic cable is made from two bend sensitive materials: plastic or glass. It is broken easily when kinked or bent too tightly to exceed the minimum bend radius of cable. Then which factor will influence bend radius? How to choose cables according to it? This blog will provide some hints.

Why Bend Radius Is Important?

When you deploy the fiber optic cable, it is inevitable to flex, pull and bend it due to the practical conditions. However, it is the bend radius that determines how much you can bend a cable. It represents as the safe value that can prevent your cable from damaging or degrading its performance. If a cable is bent beyond its allowed radius, it will generate crosstalk or interference in data transmission, or even shorten its life. That’s why it’s important to know the bend radius of the cables, especially the minimum bend radius,which is the smallest allowed radius the cable can be bent around without signal loss or impairment.

Factors Impact Bend Radius of Cable

The bend radius may differ from cables. The fact is the smaller the minimum bend radius, the more flexible the cable. Here list some factors that may affect this radius of cable.

Outer Jacket Thickness

The thickness of the outer jacket of a fiber patch cable intended for bending will influence the potential minimum curve radius. Generally speaking, if the outer jacket is thick, the fiber patch cable will have a smaller bend radius. This can be translated by the fact that when the cable is bent, the stretching force makes the outer jacket thinner and even broken. Therefore, if the outer jacket is thin itself, the external tension may deform of break the fragile cable.

Material Ductility

Cables are manufactured by different materials, and this will affect the radius of the bend. Ductility refers to the flexibility of material under tensile stress or stretching force. If you would like to obtain small curve radius, you should choose cables made of highly ductile materials like copper. An alternative such as glass is more brittle than flexible.

Core Diameter

The large core diameter determines the small bend radius. Simply put, the single mode fiber has a smaller diameter than multimode fiber, and the single mode fiber cable bears less weight or bending than multimode fiber cable. That’s why the bending radius of single mode fiber optic cable is larger than the multimode fiber optic cable.

How to Choose Fiber Optic Cables based on Bend Radius?

Generally, the multimode fiber optic cable is recommended if the bend radius is the only consideration. And another option is BIF fiber cable. BIF means the bend insensitive fiber which enables tight curve radius when cables are bent or twisted. FS adopts it in producing both multimode and single mode fiber cables to endow them much smaller bend radii than ever before. It realizes more convenience in cable management, as well as less signal loss and less cable damaging. Here is a bend radius chart of BIF fiber optic cable.

Fiber Cable Type	Minimum Bend Radius
OM3/OM4 MTP BIF	7.5mm
Single Mode OS2 MTP BIF	10mm
Uniboot OS2 LC BIF	10mm
Uniboot OM3/OM4 LC BIF	7.5mm

Conclusion

To sum up, the bend radius of cables is paramount for fiber patch cable installations. Factors which influence the minimum radius of fiber optic cable include the outer jacket thickness, material ductility and core diameter. To protect the integrity and performance of cable, we shall not bend the cable beyond its allowed radius.