Fiber optic cable is favored for today's high-speed data communications because it eliminates the problems of twisted-pair cable, such as near-end crosstalk (NEXT), electromagnetic interference (EMI), and security breaches. Fibre Optic Cable is the preferred option in the interconnecting links between floors or buildings, is the backbone of any structured cabling solution. While, making the right decisions when it comes to Data Network cabling is difficult as it can make a huge difference in the ability of your network to reliably support current and future requirements. There are many factors to consider and today I will guide you through the many options available and find the best one suits your application.

1. Multimode Fiber Cable Or Single-mode Fiber Cable

There are two basic types of fiber: mulitimode and single-mode. Both types consist of two basic components: the core and the cladding which traps the light in the core.

Multimode fiber cable

Multimode fiber, as the name suggests, permits the signal to travel in multiple modes, or pathways, along the inside of the glass strand or core. It is available with fiber core diameters of 62.5 and a slightly smaller 50 microns. The problem with multimode fiber optics is that long cable runs in multiple paths may lead to signal distortion. This can result in incomplete and unclear data transmission.

Applications covering short distances can use multimode fiber optic network cable. Ideal uses for such kinds of cables are within data center connections. Multimode cables are economical choices for such applications. There are various performance levels within the multimode fiber optic cable such as OM3 cable for distances within 300 m, OM4 cable supports Gigabit Ethernet distances within 550m and 10G applications.

Single-mode fiber cable

Single-mode fiber cables offer a higher transmission rate. These cables contain a tiny core that measures about five to ten microns. These tiny cores have the capacity to eliminate distortion and produce the highest transmission speeds. Single-mode fiber generally has a core that is 8.3 microns in diameter. Singlemode fiber requires laser technology for sending and receiving data. Although a laser is used, light in a single-mode fiber also refracts off the fiber cladding. The presence of high intensity lasers helps transfer data across large distances. Singlemode has the ability to carry a signal for miles.

Single mode is used for long haul or extreme bandwidth applications, gives you a higher transmission rate and up to 50 times more distance than multimode, but it also costs more. The small core and its single lightwave virtually eliminate any distortion that could result from overlapping light pulses, providing the least signal attenuation and highest transmission speeds of any fiber cable type.

The best choice to choose multimode optical cable when the transmission distance is less than 2km. In the other sides, use single-mode optical cable when the transmission is more than 2km. Although the core sizes of multimode and singlemode fiber differ, after the cladding and another layer for durability are applied, both fiber types end up with an outer diameter of about 250 microns. This makes it both more robust and easier to work with.

2. Indoor Cable Or Outdoor Cable

The major difference between indoor and outdoor cables is water blocking. Any conduit is someday likely to get moisture in it. Outdoor cables are designed to protect the fibers from years of exposure to moisture.

Indoor Cables

Indoor cables are what we call "tight-buffered" cables, where the glass fiber has a primary coating and secondary buffer coatings that enlarge each fiber to 900 microns—about 1mm or 1/25-inch—to make the fiber easier to work with. Indoor cables are flexible, and tough, containing multiple Tight Buffered or Unit Cord fibers.

Types Of Indoor cables available

Simplex and Zip Cord: Simplex Fiber Optic Cables are one fiber, tight-buffered (coated with a 900 micron buffer over the primary buffer coating) with Kevlar (aramid fiber) strength members and jacketed for indoor use. The jacket is usually 3mm (1/8 in.) diameter. Zipcord is simply two of these joined with a thin web. It's used mostly for patch cord and backplane applications, but zipcord can also be used for desktop connections. They are commonly used in patch cord and backplane applications. Additionally, they can be utilized for desktop connections. These cables only have one fiber and are generally used indoors.

Distribution cables: They contain several tight-buffered fibers bundled under the same jacket with Kevlar strength members and sometimes fiberglass rod reinforcement to stiffen the cable and prevent kinking. These cables are small in size, and used for short, dry conduit runs, riser and plenum applications. The fibers are double buffered and can be directly terminated, but because their fibers are not individually reinforced, these cables need to be broken out with a "breakout box" or terminated inside a patch panel or junction box. The distribution cable is smaller and used in dry and short conduit runs, plenum and riser applications, is the most popular cable for indoor use.

Breakout cables: They are made of several simplex cables bundled together inside a common jacket for convenience in pulling and ruggedness. 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, is ideal for industrial applications where ruggedness is important or in a location where only one or two pieces of equipment (such as local hubs) need to be connected.

Outdoor Cables

Optical fiber in outdoor applications requires more protection from water ingress, vermin, and other conditions encountered underground. Outdoor cables also need increased strength for greater pulling distances. Buyers should know the potential hazards that the cables will face, for example, if the cables will be exposed to chemicals or extreme temperatures.

Loose Tube cables: These cables are composed of several fibers together inside a small plastic tube, which are in turn wound around a central strength member and jacketed, providing a small, high fiber count cable. This type of cable is ideal for outside plant trunking applications, as it can be made with loose tubes filled with gel or water absorbent powder to prevent harm to the fibers from water. Since the fibers have only a thin buffer coating, they must be carefully handled and protected to prevent damage. It can be used in conduits, strung overhead or buried directly into the ground.

Ribbon Cable: This cable offers the highest packing density, since all the fibers are laid out in rows, typically of 12 fibers, and laid on top of each other. This way 144 fibers only has a cross section of about 1/4 inch or 6mm! Some cable designs use a "slotted core" with up to 6 of these 144 fiber ribbon assemblies for 864 fibers in one cable! Since it's outside plant cable, it's gel-filled for water blocking.

Armored Cable: Cable installed by direct burial in areas where rodents are a problem usually have metal armored between two jackets to prevent rodent penetration. This means the cable is conductive, so it must be grounded properly. You'd better choose armored fiber cable when use cable directly buried outdoor.

Aerial Cable: They can be lashed to a messenger or another cable (common in CATV) or have metal or aramid strength members to make them self supporting. Aerial cables are for outside installation on poles.

The table below summarizes the choices, applications and advantages of each.

All cables share some common characteristics. For example, they all include various plastic coatings to protect the fiber, from the buffer coating on the fiber itself to the outside jacket. All also include some strength members for pulling the cable without harming the fibers. Outdoor fiber optic cable has moisture protection, either a gel filling or a dry powder or tape. Direct-buried cables may have a layer of metal armor to prevent damage from rodents. It is advisable that you should customize your cable to make it suitable to your application when the quantity of fiber optic cables is large and also for the cost-effective reasons.

Knowing basic information about fiber optic cables make choosing the right one for the project a lot easier. It is always beneficial to konw more about fiber optic cables.

FiberStore news, the latest research achievements from a research team in the United States show, encoding information through twist beam of different shape can improve the Internet "Information Super Highway" carrying capacity, which effectively alleviate the network congestion.

Internet traffic is growing exponentially, researchers have been trying to enhance the communication capacity of fiber optic cable. A successful method used in the past 20 years, basically is to rely on the more "lane", refers to use a different color or wavelength to transmit different signals. But just like in the real highway, since the amount of "lane" is increased, each width is narrower, so the data stream can only be mixed together.

From past few years, there are a number of research teams trying to get through the shape of light beam to encode the information, in order to ease network traffic congestion, the technology used the called light property of orbital angular momentum. Currently, the network signal is the use of straight spread light beam to transmit, but the specific filters can make the beam distortions in varying degrees in the process of moving. However, the experiments results using this effect are not ideal: different shapes of light beam often mix with each other in advance distance of less than 1 metre.

But now, researchers at Boston University and the University of Southern California cooperated, found a way to make the different shapes of light beam travel separately, the transmission distance reached a record of 1.1 km.

In the experiment, the researchers designed and built a 1.1 km long glass fiber cable, the cross section has a different refractive index (used to measure the travel speed of light in a specific medium). Then, they sent beam of winding and straight along the cable.

The research team found, light output and input can be matched, show that the various shapes beam does not appear mixed. Different refractive index significantly affects only a certain shape of beam, so these different shapes of beams are moving at different speeds in the cable. "This means we can keep them separate." Research team leader, Boston University Electrical Engineer Saida Si Rama Ramachandran said.

The researchers carried out several tests using beam of clockwise and counterclockwise with varying distortion degrees, and found there are about 10 different shapes of beams can be used to transmit information. The results are exciting, because every shapes may presage the "information highway" traffic is expected to reach a whole new level. Based on this, the data stream is is further divided into narrow "lane" according to the different colors, thereby maximize the flow.

However, the laboratory results applied to real world still need time, in part because the current Internet fiber optic cable only transport straight beams. Ramachandran said, a more direct goal, may be used in server farm between servers by some large network companies like Facebook, install cables which can transmit twisted beam in short distance.

FiberStore news, with the outbreak of emerging businesses such as high-definition video, social games, cloud computing and Internet of things, explosive growth of Internet content, so that the needs of next generation of Ethernet is increasing. Although the 40G/100G standards have been promulgated, the demand is also constantly stimulated, operators also verified the 100G with a commercial ability, but its scale popularity seems to have a distance, especially for 100G. What is the reason hindering the popularization, in technically what need to improve? When can really go the way of 100G?

The too high cost hinders 100G popularity And market maturity needs 3 years

China Telecom Technology Committee Director Wei Leping said, to achieve the scale of promotion, the cost of 100G applications should be controlled at as 5-6 times as the cost of 10G, there is a certain distance currently. Ruijie experts said, from the point of the cost of optical transceiver, 100G module costs several times higher than the cost of 10G transceiver. It also requires the upstream and downstream of the industrial chain complement each other, continue working hard in chip integration, integration of optical module miniaturization and system design, to achieve cost reduction of the overall product. In addition, the architecture design of network manufacturers are also important factors, the role of the scale cost reduction such as supporting cables, wiring and tools also can not be ignored.

Overall, the 40G and 100G markets are in the early stage of market, but in contrast, the growth rate of 40G is faster than 100G, for example, Ruijie has made a considerable number of 40G commercial cases.

While the 100G standard has completed, but there are still not small challenges in the core of the optical module/high-speed signal processing technology, 100G commercial products also just launched by manufacturers. Therefore, experts believe that, the mature of 100G market is expected to take at least three years.

As we all know, the optical module technology cost is the key of the whole 100G system cost. But the 100G optical module devices are mainly controlled by foreign companies, although there are some Chinese enterprises introduced the 100G optical modules, but the quantity is too small, which virtually increases the 100G system cost.

There are still defects in technical and need to further improve the industrial chain

The 100G industrial chain including chip, optical devices, router to optical transmission system, and even the deployment, but the current situation is that, in the fiber optic module, the high-end core technology are basically controlled by foreign countries. Many experts said, the Chinese module makers have not domestic semiconductor chip production technology,  no continuous wavelength tunable lasers and high-end modulator chip, the manufacturer can do 100G optical devices is rare. Although there are more and more manufacturers to join this camp now, but many companies just re-processing of imported products, the lack of core technology, so there is no competition.

In addition to the short supply and not enough maturity of chip, optical devices and so on, some experts pointed out, the 100G industry chain supporting needs to be further improved, not only because the 100G optical network construction was just started, but also because the development of the 100G still faces challenges from the technology and market, for example, still exist cognitive gap in the line, construction, adjusting and testing, industry chain parties need to work together.

40/100G complement each other

Demand determines the market. From the current applications, in addition to some large data centers, the vast majority applications do not need the 100G bandwidth now, the bandwidth of 40G is sufficient; while the 40G products are more cost-effective than 100G products, and is expected to last a period of time, so the 40G products develop more smoothly than 100G in the moment. But apparently, the scene requires higher performance is relatively urgent demand for 100G, typical scenes such as super computing, cluster computing, etc. In the future, 40G and 100G will complement each other, service users in different application scenarios.

Splicing is needed when you need to mix a number of different types of cables (like bringing a 48 fiber cable in and splicing it to six 8 fiber cables). Fusion splicing refers to the process of joining, or splicing, two optical fibers end-to-end. The fibers are heated to the point that the ends soften and pushed together. Optical fiber fusion splices play a crucial role in the optical network.

The goal of fusion splicing is to fuse the two fibers together in such a way that light passing through the fibers is not scattered or reflected back by the splice, and so that the splice and the region surrounding it are almost as strong as the virgin fiber itself. The source of heat is usually an electric arc, but can also be a laser, or a gas flame, or a tungsten filament through which current is passed.

The Process Of Fusion Splicing

Stripping the fiber
Stripping is the act of removing the protective polymer coating around optical fiber in preparation for fusion splicing, which requires that all protective coating is removed or stripped from the ends of each fiber. Fiber optical stripping is usually carried out by a special stripping and preparation unit that uses hot sulphuric acid or a controlled flow of hot air to remove the coating. There are also mechanical tools used for stripping fiber which are similar to copper wire stripper.

Cleaning the fiber
The bare fibers are cleaned using alcohol and wipes.

Cleaving the fiber
The fiber is then cleaved using the score-and-break method so that its endface is perfectly flat and perpendicular to the axis of the fiber. The quality of each fiber end is inspected using a fiber microscope. In fusion splicing, splice loss is a direct function of the angles and quality of the two fiber-end faces. The closer to 90 degrees the cleave angle is the lower optical loss the splice will yield.

To avoid damage to the sensitive optical fibers during the fusion splicing process, special tools, heat sources and methods are used in the termination and splicing of optical fibers. The options for the protection of a fusion splice include recoating with a chemical protectant or the use of a fiber optic splice protector. Recoating is accomplished using a resin that is cured by ultraviolet (UV) light, and this is usually the preferred method of protecting fusion splices as it returns the fiber to its pre-spliced condition.

The Advantages of Optical Fiber Fusion Splicing

1. Fusion splicing is very compact
2. Fusion splicing has the lowest insertion loss
3. Fusion splicing has the lowest back reflection (optical return loss ORL)
4. Fusion splicing has the highest mechanical strength
5. Fusion splicing is permanent
6. Fusion splicing can withstand extreme high temperature changes
7. Fusion splicing prevents dust and other contaminants from entering the optical path

Fusion splices give very low back reflections and are preferred for singlemode high speed digital or CATV networks. Current fusion splicers are either core or cladding alignment. Using one of these methods the two cleaved fibers are automatically aligned by the fusion splicer in the x,y,z plane, then are fused together. Prior to removing the spliced fiber from the fusion splicer, a proof-test preformed to ensure that the splice is strong enough to survive handling, packaging and extended use.