With so many fiber optic cables to choose from, one might wonder where to start. This article will guide you on the right path in the decision-making process. Let’s start with the broad classification of fiber optic cables. Next you can make a “one or the other” decision.
1. Multi-mode or single-mode?
1) Multimode cable-application
Multimode fiber is used to transmit large amounts of data over a relatively short distance (compared to single-mode fiber). Common applications include data centers and other local area network applications. Please note that the multi-mode distance capability has been increasing in recent years.
For some applications, multi-mode fiber optic cables now provide an economical alternative to single-mode cables. Multiple data streams can be simultaneously transmitted via multimode cables with larger cores (50 or 62.5 m).
2) Single-mode cable-application
Telecom companies and cable TV companies use single-mode cables for long-distance signal transmission. Business parks and other institutions also use single-mode cables for longer cable runs, such as connections between buildings.
Design: The core diameter of a single-mode fiber is very small (9 μm), so only one mode of light can pass through at any time.
This feature reduces attenuation and enables light to be transmitted over long distances. Although the purchase price of single-mode cables is generally lower than that of multi-mode cables, single-mode transceivers and network interfaces are generally more expensive than those used in multi-mode systems.
2. Simplex or duplex?
Application: Simplex and duplex cables are usually used for fiber patch cables and desktop installations, and do not require high fiber counts.
Design: The single-core cable contains a single 900 μm covered fiber or a combination of 900 μm covered fibers, covered with aramid yarn strength members, and the outer sheath diameter is between 3, 2, 1.8 and 1.6mm. The twin-core cable consists of two 900µm coated fibers surrounded by aramid yarn strength members, and the outer sheath diameter varies from 3, 2, 1.6 and 1.2mm.
3. Loose tube or tight buffer?
1) Loose tube cable
Application: Loose tube cable is ideal for long-distance applications outside the factory, requiring high fiber counts. The cable is designed to withstand harsh outdoor environments; the non-sheathed fiber of the cable can expand and contract freely with temperature changes.
Design: The fiber in the loose tube cable is surrounded by a water-blocking component (gel or dry water-blocking material).
Although loose tube cables are designed to withstand humid outdoor environments, they are not designed to be submerged in water, but to be in contact with water. Terminal loose tube fiber-The fiber in the filled hose of the cable has a very thin layer of acrylic coating with a diameter of 250 µm. Before wiring, the optical fiber must be put into a small plastic tube (called a junction box or junction box). The tubes protect the fine fibers, making them easier to handle when terminal and connected to network equipment.
2) Fastening buffer cable
Application: Fastening buffer cable is generally used indoors. A tight buffer (cable jacket) encapsulates each optical fiber. The 900-micron buffer can directly terminate the fiber without the need for a junction box, saving a lot of time. These cables usually do not provide protection against water migration, nor do they well isolate the expansion and contraction of fibers from other materials due to extreme temperatures. A tight-buffer cable, also known as a premise or distribution cable, is ideal for cable installations indoors.
Design: The tight buffer cable has two protective coatings; a 900-micron PVC sheath and a 250-micron acrylic coating, all wrapped in an external PVC sheath.
4. Distribution or breakthrough?
1) Distribution Cable
Application: Wiring is suitable for connecting multiple optical fiber networks in a public location, such as patch panels or communication cabinets. The optical fibers in the distribution cable have their own 900-micron independent cable jacket. This space-saving feature can bundle up to 144 optical fibers in the cable. The fibers in the “micro-distribution” cable do not have a 900-micron tightly cushioned PVC sheath, but instead, contain color-coded 250-micron acrylic-coated fibers.
Due to the reduced diameter of individual fibers in the cable, the micro-distribution cable may contain 432 or more fibers. One disadvantage of the micro-distribution cable is that the unsheathed fiber needs to be terminated with a junction box.
Design: The distribution cable contains 250µm-900µm fibers, color-coded for easy identification. The cable includes aramid yarn reinforcement members and a thick outer sheath that provides protection and reinforcement during cable installation. If needed, cables can be purchased with interlocking armor.
2) Breakout cables
Application: Breakout cables are ideal applications where optical fibers are directly connected to equipment, including local hubs. In addition, the robust design of the disconnect cable makes it ideal for use as a drop cable.
Design: The difference between a leaky cable and a power distribution cable is that each fiber in the leaky cable is tightly buffered by 900 microns and surrounded by aramid yarn, and all fibers are wrapped in a 2 mm or 3 mm In the PVC sheath. Then all these 2 or 3 mm fibers are wrapped in a jacket. This extra sheath can save a lot of time and installation costs, especially when the optical fiber is terminated with a connector. One disadvantage of the leaky cable is that the fiber sheath occupies the space inside the cable, so the leaky cable cannot contain as many fibers as the distribution line. The number of fibers in the missing cable is usually 2-24 (up to 48).
5. Is it Plenum or standpipe?
Static pressure cable: Static pressure cable is a channel for circulating air in a building. The static pressure cable (OFNP) has a fire rating, allowing it to pass through the static pressure space.
Rated riser cables: The riser cables (OFNR) can be laid between floors, but cannot pass through the static pressure box.
Low-smoke halogen-free cables: low-smoke halogen-free cables produce very little smoke and harmful halogen compounds when they burn.
6. Final Considerations
Determine the cable path before ordering the cable. This will enable you to determine the length of the cable you need and the degree of physical protection the cable will require. It is worth noting that the new bend-insensitive optical fiber enables the optical cable to pass tight turns with little or no reduction in signal propagation. This new type of optical fiber greatly expands your cable routing options. It is strongly recommended that you “prove” your network in the future by ordering cables with a higher number of fibers than the current requirements. Compared with the cost of installing optical fibers in the future, optical fibers are relatively cheap.
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