There are several types of fiber optic cables. End users without much background of fiber optic often face trouble to select suitable type of fiber optic cable. The design team of cable manufacturers will be capable of supporting the end user to select suitable type of cable for their project. We can group the type of fiber optic cables as below;
Simplex Cables: Simplex cables are single fiber cables made of tight-buffered (coated with a 900 micron buffer over the optical fiber) fiber covered with aramid yarns and sheathed with PVC or LSZH material. Simplex cables for indoor use. The jacket is usually 2mm or 3mm in diameter.
Duplex Cables: As the name indicates, Duplex cables have two fibers tight buffered with an elastomeric material or PVC or LSZH material. Duplex cables are Zipcord type means two of the simplex cords are joined with a thin web. It’s used mostly for patch cord and backplane applications, but zipcord can also be used for office connections.
Distribution cables: Distribution cables have several tight-buffered fibers bundled under the same jacket with Aramid yarn strength members. Several tight buffers can also be stranded around a central strength member, which is typically a fiber reinforced plastic rod. Central strength member is provided as anti-buckling element and to prevent kinking. These cables are used for short, dry conduit runs, riser and plenum applications. The tight buffered fiber can be directly terminated with connector.
Breakout cables: They are made of several simplex cables bundled together. This is a strong, rugged design, but is larger and more expensive than the distribution cables. It is suitable for conduit runs, riser and plenum applications. Because each fiber is individually reinforced, this design allows for quick termination to connectors and does not require patch panels or boxes. Breakout cables can be more economical where the fiber count is small and distances too long.
Loose tube cables: These cables are composed of several fibres together inside a small polymer buffer tube or tubes, which are stranded around a central strength member and jacketed, providing a small, relatively high fibre count cables typically up to 288F. This type of cable is ideal for outside plant trunking applications, as it can be made with the loose tubes filled with gel or water absorbent powder to prevent harm to the fibres from water. It can be used in ducts, strung overhead or buried directly into the ground. Since the fibres have only a thin buffer coating, they must be carefully handled and protected to prevent damage. Fibers inside the loose tube are free to move inside it. The fibers inside the tube will have excess length compared to the linear length of the tube.
Ribbon Cables: When higher packing density are required such as high fiber count cables but reduced diameter, Ribbons are used in the cable. In conventional ribbon cables, flat ribbons in which fibers are positioned in flat structure and then covered by a matrix material. Fibers are laid out in rows, typically in numbers of 4, 6, 8 or 12 fibres, and laid on top of each other. There are different types of Ribbon cables such as Loose tube Ribbon cables where the flat ribbons are placed in loose tubes and multiple loose tubes are stranded over a central strength member. Another type is Slotted core ribbon cables where flat ribbons are placed in slotted core built of polyethylene. Recent development is the free-form ribbons or flexible ribbons bundled with a yarn or bunching tape and several bundles are grouped in the center which is then wrapped with a swellable tape. Central tube flat ribbon cables are also popular, in which the central tube is filled with gel.
Armoured Cable: Cable installed by direct burial method in areas where rodents are a problem usually have metal armouring between two jackets to prevent rodent penetration. Armoring can be done either by metallic element or non-metallic element. Steel tapes or ECCS tapes can be used in Corrugated armoured cables. Galvanized Steel wires are used in steel wire armoured cables. These two are metallic armoured cables and shall be grounded properly. Non-metallic armouring can be done by glass yarns, or tapes or FRP rods.
Aerial cables: Aerial cables are Outside Plant (OSP) cables for installation on poles. There different types of aerial cables such as Lashed aerial cabkes, Figure-8 Self-supporting aerial cables, All Dielectric Self-supporting aerial cables (ADSS), and Aerial drop cables. Lashed aerial cables can be lashed to a messenger or another cable (common in CATV). ADSS cables have aramid or glass strength members to make them self supporting. Figure-8 cables will have a stranded messenger wire attached to the cable body through a neck/web.
Optical Ground Wires (OPGW): An OPtical Ground Wire (OPGW) also known as an optical fiber composite overhead ground wire is used in overhead power lines. OPGW cables combine the functions of grounding and communications. An OPGW has a central tube structure with single or multiple optical fibers in it, which is then surrounded by layers of steel and aluminum alloy wires. These cables are installed on the tops of high-voltage electricity pylons. The optical fibers in an OPGW cable can be used for high-speed transmission of data, either for the utility company’s own use of protection and control of the transmission line, and for the utility’s own voice and data communication. Some utility companies lease or sell the fibers to third parties to serve as a high-speed fiber interconnection between cities. The metallic conductors of OPGW serves to bond adjacent towers to earth ground, and shields the high-voltage conductors from lightning strikes. Single mode optical fibers with low transmission loss, allowing long distance transmission at high speeds are used typically in an OPGW.
Submarine Fiber Optic Cables: Submarine fiber optic cable is an optical cable laid on the seabed between land-based stations to carry data across continents crossing oceans. The first submarine communication cable that was copper cable was laid beginning in the 1850. Submarine fiber optic cables are made with several elements to protect the cable under the sea. These are heavy cables with multiple layers of protection to withstand attacks from sharks and other sea creatures. The first submarine telephone cable to use optical fiber was TAT-8, which went into operation in 1988.
Sensor Cables: Fiber optic cables can be used not only for data transmission, but also for measuring temperature, strain, and acoustic signals. Optical fibers used in such applications are called sensor fibers. Sensor cables can work in harsh environments such as Oil and Gas, Military, Mining etc. Distributed Temperature Sensing (DTS) and Distributed Acoustic/Vibration Sensing (DAS & DVS) solutions, enable efficient monitoring of critical infrastructures and buildings such as rail and road tunnels, pipelines, bus ducts and parking garages.
Flame Retardant Cables: Flame retardant fiber optic cables are used in indoor and indoor-outdoor environments where there is a possibility of cables catching fire. Flame retardant fiber optic cables use Low smoke zero halogen materials or PVC for inner and or outer sheaths in order to reduce the risk of propagating the flames in case the cable is exposed to fire.
Fire Resistant Cables: Fire resistant cables as the name indicate are resitant to fire and are used in critical service locations. For critical services, the communication shall be uninterrupted to prevent to reduce the damage due to fire. Fire resistant fiber optic cables use several layers of fire resistant materials such as mica tapes, steel tubes to protect fibers, and to reduce the use of flammable materials. One of the international standards for fire resistance requires that cable shall ensure continuity even after 90 minutes of fire enviroment.
The above are just a few type of fiber optic cables. If you know more types, please mention them in the comment box below.
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