Fiber cable installations are an art and science. Mainly, it requires fiber specialists to consider lots of factors, including cable lengths, fiber cable bend radius, connectors, splices, and splitters. Today, we are going to discuss the fiber bend radius, one of the factors everyone should know about when micro trenching. Bend loss can literally make micro-cracks and break light transmission—how the optical signal passes through the glass fibers. If you want to learn more about the fiber bend radius, please continue reading the guide to fiber optics.
Table of Contents
- 1. Fiber Optic Bend Radius – What is it?
- 2. Minimum Fiber Optic Cable Bend Radius
- 3. Factors that Impact Fiber Optic Bend Radius
- 4. What to Use? Bend Insensitive Fiber Cable
- 5. Radius or Diameter? Which one’s Better to Work With?
1. Fiber Optic Bend Radius – What is it?
“Looping optic fiber cables incorrectly can lead to fiber damage and signal loss”
First of all, fiber optic bend radius refers to the maximum angle at which its glass fibers bend without breaking. This ensures fiber-optic communication (all the data and signals passing through the optic fiber cable) go back and forth smoothly. Moreover, the bend radius prevents the fibers within the cable to snap and stop working. Calculating the fiber bend radius is important for fiber distribution and fiber cable protection. This way, it’s easier to determine it and use a standard ruling for it to avoid fiber failures.
2. Minimum Fiber Optic Cable Bend Radius
“Operators use optical fiber snowshoe to limit the fiber bend radius on aerial installations”
The following formula is used to calculate fiber bend radius:
Bend Radius = Cable Outer Diameter x Cable Multiplier.
The cable multiplier is determined by industry standards and cable type.
For inside plant cable, there’s always a minimum radius for fibers to consider. It all depends on if the cable is loaded (with tension) or unloaded (without pull load.) A good rule of thumb is that if the cable is loaded, the minimum cable bend radius is about 10x the cable’s diameter. However, on the other hand, if the fiber optic cable is unloaded, the minimum fiber bend radius recommended is about 15x said measure.
Despite all that, operators often go with the bigger minimum bend radius measure to avoid any future problems once installed. The reason? The tension that pulling fiber through the fiber cladding increases the chances of bending and breaking.
3. Factors that Impact Fiber Optic Bend Radius
“Fiber bend radius depends on lots of factors”
There is a critical element taking part in how the fiber optic bend radius works. However, the more flexible the fiber cable is, the smaller the minimum bend radius is.
To avoid tensile load and determine the cable’s tensile strength, it is necessary to do some cable prepping. In addition, choosing the correct cable to avoid breaks and snaps depends on the fiber cable core diameter. For this reason, the bigger the cable’s diameter, the smaller the bend radius. The reason is that the smaller the diameter is, the lower the weight and tension the cable carries.
“Core diameter is crucial to consider”
Cable outside diameter
Paired with the core diameter factor, the thickness of the cable’s outer diameter plays a big part. The rule is simple; the thicker the outer jacket, the smaller the fiber optic bend radius. Thick outer jackets resist stretching better than thin ones. The reason is that the forces stress the outer jacket, making it prone to breaks.
The material of the cable also plays a big role when it comes to fiber optic bend radius. Choosing the best one for your needs is crucial, as it can do more harm than good in the future. Furthermore, the more flexible the material is, the more it will bend without representing an issue for the fibers inside.
“The more flexible the material, the better”
In addition, said ductility will determine how flexible the cable will be when under extended tension, stretching, and pulling. For example, copper-filled cables are significantly more flexible than glass fiber-filled ones, as glass is more fragile and breaks easily.
4. What to Use? Bend Insensitive Fiber Cable
Fortunately, there’s always a solution for every life problem, at least when it comes to fiber optic bend radius issues. Bend insensitive fiber optic cable is here to save operators and users from trouble, allowing them to enjoy FTTH. Regardless of the type you need, whether it’s single-mode or multimode, there’s a bend-insensitive fiber optic cable for you.
“Using the right cable will allow you to enjoy FTTH without trouble”
These cables transmit the data and signal, experiencing minimal loss even when bent over the recommended measures. Bend insensitive fiber optic cables have a ring inside that surrounds the core of the cable. This ring, also called trench, makes the light reflect back to the core, avoiding refraction and signal loss. Operators usually use a bend insensitive fiber optic cable only when the situation calls for it, for example, in a crowded and narrow area where tight bends are needed.
Bend Insensitive Multimode Fiber Optic Cable
“Multimode cables allow the deployment of more than one fiber optic cable at once”
These cables transmit the data and signal, experiencing minimal loss even when bent over the recommended measures. Bend insensitive fiber optic cables have a ring inside that surrounds the core of the cable. This ring, also called trench, makes the light reflect back to the core, avoiding refraction and signal loss. Operators usually use a bend-insensitive fiber optic cable only when the situation calls for it. For example, in a crowded and narrow area where tight bends are needed.
Bend Insensitive Single-mode Fiber Optic Cable
“Single-mode cables allow the installation of only one cable at a time”
On the other hand, when it comes to bend insensitive single-mode fiber optic cables, they only pass one optic fiber at a time. The same as their counterpart, single-mode ones have the strength to carry more weight and tension than normal single-mode cables. Also, they are significantly more flexible, allowing operators to loop them around on loops as small as 5mm. These cables also have bend-induced attenuation reduction features and display less signal and data loss than normal cables.
5. Radius or Diameter? Which one’s Better to Work With?
“Radius or Diameter? Both numbers are vital”
Usually, fiber optic cable manufactures won’t apply a warranty on damaged cables. Especially if the cable stopped working due to negligence or improper installation. To avoid this from happening, operators should know everything about fiber optic bend radius. From how to measure it to how to install it properly, everything is important. However, although most operators work with the cable’s radius, manufacturers recommend also work considering the cable’s diameter. This data will come in handy when calculating how much the cable bends in every cranny when pushed through ducts.
“Choose the right cable for your needs”
Knowing fiber cable management will avoid fiber optic cables from experiencing signal loss or performance loss. In conclusion, choosing the best fiber optic cabling at the initial installation can make the difference between fiber bend radius and cable installation. If looking for more information about the application of fiber, contact us. We are a cable manufacturer who provides fiber cable assemblies for you. And our knowledgeable team of fiber specialists offers you a wide range of application solutions.