The core of optical fibers can be plastic (used for very short distances), but most are made from glass. And glass optical cables are made from silica, which, in pure form, has a very low loss in infrared region of the optical spectrum. Designed for longer distance, very high-performance data networking and telecommunications, fiber optic cable uses light to transmit information while the copper wire uses electricity.
A fiber optic cable is composed of the core, cladding, coating, strengthening fibers and cable jacket, with its core and cladding being the two main elements. The core is the light transmission area of the fiber. The cladding is the layer completely surrounding the core. Surrounding the cladding is usually another layer, called a coating.
The principle of light transmission in an optical fiber is known as the total internal reflection, which states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; instead, the light bounces back in. Based on this principle, light can move easily down the fiber-optic line. When this principle is applied to the construction of the fiber-optic strand, it is possible to transmit information down fiber optic cable in the form of light pulses. The core must be a very clear and pure material for the light or in most cases near infrared light (850nm, 1300nm and 1500nm). That’s why glass and plastic are the main materials for optical fibers.
types of Fiber Optic Cable by Application
We’ve talked about fiber optic cable types from the perspective of fiber mode or material a lot in the past. Today we will give you a glimpse of fiber optic cable types from the perspective of their applications. According to the places where optical cables are deployed, they can be divided into indoor fiber optic cables and outdoor fiber optic cables.
Indoor Fiber Optic Cables
For fiber optic cables that are designed for indoor environments, they are generally versatile, convenient, and relatively inexpensive. It is common to find these cables in buildings, offices, and homes. Though indoor fiber optic cables experience less temperature and mechanical stress when compared with the fiber cables used outdoors, the key characteristic of indoor cables is fire-resistance.
Outdoor Fiber Optic Cables
There are several types of fiber optic cables for outdoor applications, such as underground fiber cables, direct buried fiber cables, and aerial fiber cables, each of which has its differences in design and characteristics.
Underground Fiber Cables
Underground fiber cables are generally pulled within a conduit which is buried underground, usually 1 to 2 meters deep, to reduce the possibility of being dug up. Lubricants are added in the outdoor cable design to reduce friction on high-pulling tension.
Direct Buried Fiber Cables
Direct buried cables are buried underground like underground cables, yet without conduit. Therefore, these cables must be able to withstand dust, pressure or rodent chewing. Compared with the underground cables with conduits, direct buried cables are more solid.
Aerial Fiber Cables
Aerial cables are placed from poles or pylons or mounted on buildings. The deployment environment protects aerial cables from man-made damage or theft but increases the risk of being destructed by natural elements such as storm, wind, and ice.
Submarine/Underwater Fiber Cables
As the name suggests, the submarine or underwater cables must have the protection against water and moisture as the result of the specific outdoor environments they are placed. Considering that factor, most of the underwater cables now build with a gel or absorbent powder or tape, which generally applies to loose tubes or ribbon cables.
Though indoor cables and outdoor fiber optic cables have so many differences, nowadays there are some cables applicable for both indoor and outdoor applications, which are designed to meet the rigorous environment of the outdoors but also meet the flame rating requirements applied indoors.
Contact Person: Mrs. Alice